You probably have plenty of apps on your smartphone, but when was the last time you paid for one? For most, the answer is probably not recently – unless you’re between the ages of 25 and 34.

According to a report from Gartner more than half of smartphone users spent no money at all on either paid-for downloads or in-app transactions within the last three months, though spending on in-app transactions is on the rise.

Gartner research director Stéphanie Baghdassarian pointed out in-app spending was up 26 percent from 2015 to a mean of $11.59, while paid download spending crept up by just 4 percent to a mean of $7.67.

Gartner’s survey of nearly 3,000 respondents in each category found higher app spending levels (above $15) were more common for in-app transactions rather than paid-for downloads. Baghdassarian said this is “largely because the vast majority of paid-for mobile apps have a price tag of $1.99 or less, while the activation of in-app transactions usually means that the user has found value in an app and will be happy to spend more on it.”

Older millennials between the ages of 25 and 34 were the largest spenders in both categories with in-app transactions averaging $19 per quarter and paid downloads averaging $13.40. Young Generation X individuals aged 35 to 44 were the second-biggest spenders, though they paid more for in-app transactions than downloads.

“As respondents grow older, they seem to be less keen to spend money within an app, and would rather pay for an app upfront. The 18-to-24 age segment shows low average spending on paid-for downloads and high average spending on in-app transactions, at $3.80 against $12.10. This trend is likely to continue as these young millennials grow older,” Baghdassarian added. “Consumers’ increased preference for in-app transactions is a clear sign that technology product marketing leaders working for app providers should invest in this model to provide flexibility in how they engage with app users.”