With last summer's release of ioses 9.1, a gaggle of new emoji was set loose beneath our thumbs. And even though we were all hotly anticipating the taco and burrito emoji, those new symbols weren't the most popular of this recent crop. Which one was the most-used? You may be surprised to learn it's "Face with Rolling Eyes," as the emoji is formally known. Given the Internet's penchant for sarcasm, maybe it was to be expected.

According to Unicode partner EmojiXpress, the disdainful emoji won handily, showing up in 14 percent of texts containing the ioses 9.1 emoji sent from EmojiXpress' keyboard app during the last two weeks of January.

That's a lot of qualifiers to judge the new emoji's popularity though, right? How many people are actually using the EmojiXpress keyboard? How many people have downloaded ioses 9.1? Well, EmojiXpress sampled 30 million emoji sent using its app, and though Apple doesn't release hard numbers, with over 1 billion ioses devices out there, we can assume hundreds of millions of people had upgraded to ioses 9.1 by late January.

Still, you can really only definitively say that Face with Rolling Eyes is EmojiXpress' most popular new emoji. Things get a little more complicated when you start looking at other platforms, especially the platforms where emoji-loaded mobiles communications are the norm.

Fooji, the app where you order food using nothing but (you guessed it) emoji has specific munchables at the top. "Consistently, we see the pizza, noodle bowl, and pasta emoji at the top---nationwide," says Fooji creator Gregg Morton. He says the newly added taco emoji has easily been the most popular emoji of the 9.1 release, but that it's a little too early for it to break into one of the top spots.

Over at Tinder, the heart emoji are the most-used, to what I can only imagine is absolutely no surprise (although... eggplant?). Social media marketing firm Zoomph tracks how emoji are used across different platforms: On Twitter, it's ? (still); on Facebook it's also ?; on Instagram it's ☕️ (all that coffee art); and on Google+ (lol), it's ?. (Interpret that as you will.)

Part of the problem in determining emoji rankings is that we haven't been tracking emoji popularity conclusively for very long. Emoji Tracker, which launched in 2013, was the first definitive studier of real-time emoji usage, and it's still the only organization keeping tabs. Emojipedia founder Jeremy Burge says Emojipedia launched its popularity tracker in September 2013, so keeping an eye on these rankings is a relatively new ordeal---and, everyone's tracking something different. Emoji Tracker tracks real-time Twitter data; Emojipedia uses internal data, so how often an emoji is accessed on its site (a lot of people bookmark it for desktop emoji use); EmojiXpress also tracks its internal use; people using its emoji keyboard app. It's all a bit messy, but it does give you a glimpse at their diversity.

There are a few conclusions (or semi-conclusive conclusions) we can make about cross-platform emoji use. Emoji are flatlining on Twitter and skyrocketing on Instagram, according to Zoomph, which measures emoji use on social media. (Zoomph also said that Face with Rolling Eyes isn't experiencing any real growth across social networks.) But---of course---Zoomph isn't analyzing texts, so maybe that's really where Face with Rolling Eyes is hitting its stride.

Gretchen McCulloch, a linguist who specializes in Internet communication, offers up one example of how the medium definitely changes the language. A study of Indonesian users' texting versus their tweeting found that in texting, people were more informal, using words with repetitive letters to indicate emphasis, like "waaaaay," or "nooooo."

"It seems intuitive this would apply to emoji," McCulloch says. "There's a tendency to use object emoji in public places, or if you use an emotional emoji, just one---whereas you will send a friend five Tears of Joy emoji in a row."

There are definitely emoji preferences across platforms, but one thing seems to be true of them all: Everyone is a little slow jumping on board with the new emoji of ioses 9.1.

"The new emoji are only five percent of the emoji used on a daily basis [in EmojiXpress]," says EmojiXpress CEO Tayfun Karadeniz. "So either they are not as popular as the others or adoption is taking a bit more time." Shockingly, taco, burrito, and cheese---which we've been obnoxiously crying out for---didn't crack into this preferred tier. "The new emoji have not even come close the popularity of the old ones," says Karadeniz. "The old ones" being the emoji released in ioses 6.0, the last time there was a big update. "So there are none [from ioses 9.1.] 'rising to the top' at the moment."

It's all a lot of effort for inconclusive results. "At a certain point, it's like if you started ranking words,"McCulloch points out. "'With' and 'and' will have a higher frequency, but does that really tell you anything?" But that doesn't mean we shouldn't be tracking emoji use: We should just do it differently, tracking emoji popularity over time. Like a Google Ngram for emoji, McCulloch suggests. "Maybe in 10 years, we would go back and say, 'Oh in 2014, people were really into this emoji' and we could relate that to something happening at the time."

So how long does it take for an emoji to become popular? "Face with Tears of Joy" is one of if not the most popular emoji, deemed 2015's Oxford English Dictionary's word of the year, and has long dominated Twitter. But let's try and track its ascent, if we can.

Face with Tears of Joy was approved by Unicode in 2010, and has enjoyed a spot in the "most popular" category for all of 2015, according to Emojipedia. It's hard to tell when exactly the emoji broke into the top echelon, but the earliest screenshot of Emojipedia available via Wayback Machine shows that on August 1, 2013, Face with Tears of Joy was included in its popular emoji category. According to another Wayback Machine screenshot, Face with Tears of Joy was the second-most-used emoji on Twitter spot as of July 26.

Just to offer a little perspective: EmojiXpress says Face with Years of Joy has been sent over 7 million times, while the most popular new emoji Face with Rolling Eyes was sent about 290,000 times during the same time period. In Face with Rolling Eyes's defense, it's still an emoji baby, and you get used to your old standbys---especially when they show up in the tab containing your recently used emoji, often the first place your thumb goes.

"It seems to me a lot of people use the same emoji frequently, more than seeking out new ones," says Emojipedia's Burge. He also points out that we come to cherish certain emoji because they start to take on personal significance. "Sometimes a particular emoji may get an alternative meaning among a friendship group, which encourages its ongoing use." And vice versa for new emoji: You're taking a big risk using one if the recipient just doesn't understand---or worse yet, hasn't upgraded to ioses 9.1 or has an androids phones and can't even see it. "I might stick to a 'safe' emoji that I know works on all platforms," he says.

That discoverability is part of what's standing in new emoji's way. "As we add more emoji, they get harder to find," says McCulloch. "There's a reason we go to our recently used." She says maybe a reimagining of the emoji keyboard, or changing how discovery works would improve this. Hopefully it will, because there will never been such a thing as too many emoji.