At this point, wearing leggings is no longer about fitness—it’s about function. Exhibit A: Sales of stretchy pants surpassed denim—the fabric of the people—for the first time this year. But until Business of Fashion published its long read on how America became a nation of yoga pants, it was hard to tell how many heart emojis (err: peach emojis?) the bottoms got.

Let’s just say a lot. People currently spend $1 billion on leggings and active bottoms, according to BoF. It’s a massive figure, for sure, and it begs the question: Why do we love leggings so much? Obviously…the answer varies. But if we look at the different instances in which people purchase their beloved bottoms, we can more easily assess why they’ve become so valuable.

As BoF notes, the dominance of athleisure in the fashion industry (it’s currently the fastest growing category) has made casual dressing apropos for work and leisure, and sure, working out. In other words, that leggings can “do all” is their real appeal. “Consumers expect a lot more,” Sun Choe, chief product officer at Lululemon, tells BoF. “They’re expecting some versatility in their product.”

What BoF didn’t address in its article is this: Size inclusivity of ready-to-wear brands remains a problem. Many lines top out at between size 12 to 14, while the average American woman is a 16 to 18. Activewear brands were among the earliest in mainstream to introduce size inclusive collections—or, to offer extended sizes from the start. This allowed these brands to engage with the 67 percent of the population other ready-to-wear labels were not.

But that still doesn’t get us to a billion dollars. BoF reports that there are now 11,000 different yoga pants available, which probably helps to make up the difference.  This variety makes the possibilities for expressing one’s personal style endless. You can literally find a pair of leggings to suit any aesthetic from classic black to color-blocked to novelty dedicated to your love of everything from leopard print to Star Wars. Seriously, what’s not to love about that?

Here’s what your leggings preference says about your personality type—in case you were curious.