We all know we live in a world where there's an app for everything. But how do we really use them?

Nielsen on Thursday released a new study showing that while the number of apps that smartphone-wielding Americans use holds steady at around 26.7 per month, we're spending more time with them overall. The average person used apps for 37 hours and 28 minutes last quarter -- nearly a full work-week. And that's up from 30 hours and 15 minutes just the quarter before and a 63 percent rise over two years, the company said in a blog post.

But that doesn't mean we're using more apps. The study found that while people are dipping into their apps more, they're not necessarily downloading a wider variety of apps. Instead, they're spending more time with the ones they already have. The firm also found that more than 70 percent of all usage comes from the top 200 apps.

(Courtesy of Nielsen Company)

So what's behind the rise? Nielsen dug into its data and found that entertainment apps such as games, music and video seem to be the main culprits of the increase. Overall, smartphone users reported a 26 percent increase in the time they spend using their smartphones for the fun things in life, for an average of 13 hours and 20 minutes per month. Entertainment app users gained 13 million additional users over the past year. And, as a group, they spent nearly three hours more in apps than they did last year. That's a whole viewing of a "Lord of the Rings" movie per month.

Gaming, meanwhile, was the fastest-growing app category within entertainment. More than three-quarters of entertainment app users reported playing at least one game in the last quarter of 2014. Smartphone owners spend a little more than 10 hours playing games, which can get awfully addictive. Just ask anyone who's ever missed their train stop because they were playing "Candy Crush."

(Courtesy of Nielsen Company)

The study also found that different characteristics predict how people use apps and how many they'll use. Men, for example, use more apps than women -- 27.2, on average, versus 26.3 --  but women tend to spend about an hour more using apps overall each month.

Race was also a determining factor in how many apps people used, and for how long. African-Americans tend to use more apps, 30.3, on average, and spend nearly 43 hours using them. Hispanics, meanwhile, use fewer apps but spend nearly as much time -- 41 hours and 31 minutes -- in apps per month. Asian-Americans use an average of 28 apps per month and spend just over 37 hours using them. Nielsen found that white smartphone users use the fewest apps and spend the least time using them.

(Courtesy of The Nielsen Company)

Those results fall in line with other studies on minority technology use. For example, the Pew Center for Internet and American Life reported last year that young African-Americans, are far more likely to use social media than their white peers.

To get its numbers, Nielsen surveyed 5,000 adult smartphone users who agreed to download its monitoring software on iOS and Android devices. The group, Nielsen said, was recruited online in English and included "Hispanic, African-American and Asian-American consumer representation."