As mobile apps have become part of the daily life for tens of millions of users globally, people are spending much more time on apps, a new study from US-based app tracker App Annie found.

The report compared data from the first quarter in 2015 and 2017, showing that the time per user increased over the globe and that trend is only set to go up.

The time spent on apps grew to nearly one trillion hours last year, according to company figures. App Annie said the increase in total time is largely a result of an exploding user base.

Among the countries analyzed, South Korea, Brazil, Mexico and Japan stood out, averaging around three hours per day in the first quarter. For users in the United States, they spent an average of over two hours per day using apps, which combined equals over a month out of a year.

The study also found people used over 30 apps per month on average. Each month, people typically use over one-third to one-half of the apps on their smartphones.

The company said today consumers prefer to manage their life through apps, and apps are increasingly becoming a must-have for many businesses and industries.

From 2015 to 2017, average time spent using mobile games by users increased in all countries, according to the report.

According to global researcher SuperData, the game industry generated $91 billion in revenue worldwide in 2016 via applications, with the mobile gaming sector winning the largest share of $41 billion.