Nielsen, global leader in measurement and information, takes a look back at the State Of Appnation and how much has changed over the past year. Since Nielsen’s 2011 summary, the number of U.S. smartphone users has increased by 12.4%, with one in two mobile subscribers now owning a smartphone. With the rise in smartphone users, comes a rise in the number of apps being downloaded, as well as the amount of time users spend engaged with them.

Android and iOS users continue to dominate app downloads, accounting for 88 percent of those who have downloaded an app in the past 30 days — up 14% since last year. In fact, the number of Android and iOS users has more than doubled since last year, attracting an astonishing 84 million U.S. mobile subscribers (that’s more than the entire population of the U.K.).

According to Nielsen, the average number of apps per smartphone has jumped 28 percent since last year, from 32 apps to 41. I thought that number seemed high until I counted the number of apps I have on my smartphone: 67.

The amount of time users spend engaged per day has only risen slightly, however, the amount of time users spend in apps vs. the mobile web is now up to 81 percent. It also looks like users are exploring more unconventional apps, as the amount of time they spend within the top 50 apps has actually decreased since last year.

In case you were wondering, the top 5 apps have not changed since last year and include: Facebook, YouTube, Google Play Store, Google Search, and Gmail.

The mobile ecosystem is certainly thriving and it doesn’t look to be slowing down anytime soon — which is good news for developers. So, how many apps do you have on your smartphone?

• SourceNielsen
• ViaTechCrunch