20X20.75 LaCroix Billboards KRYoung employees of Chicago’s tech companies are buying large quantities of LaCroix sparkling water, the Chicago Tribune reports. The drink comes in 20 flavors, and stores are having trouble meeting demand.

“The millennial generation, what we’ve seen in general is they’re more focused on clean labeling, natural ingredients and healthy lifestyles,” Adam Fleck, director of consumer equity research for Morningstar, was quoted as saying in a National Association of Convenience Stores article.

Sales of sparkling water have risen about 10 percent each year, driven by consumer wellness concerns.