The vast majority of app downloads in the world are generated by free apps, reports app tracking company Distimo. According to the Dutch firm, a recent Gartner study that suggested 89 percent apps downloaded in 2012 will be free might actually overestimate the average smartphone user’s willingness to pay for an app.

In order to prove its point, Distimo analyzed U.S. download data. It found the ratio of downloads among the top 300 most popular free apps and the top 300 most popular paid apps varied by the type of app store.

According to Distimo, the iPad app store had the lowest ratio at 11x — for every one of the 300 most popular paid iPad applications downloaded, users also downloaded 11 of the 300 most popular free iPad applications. The Amazon Appstore was the second lowest, with 12x ratio of free to paid downloads for popular apps and the iPhone app store had a 15x ratio of free to paid downloads.

Unsurprisingly, Distimo found Google Play had the highest ratio, reporting 82 downloads of popular free apps for every popular paid app downloaded through the service.

Next Distimo analyzed worldwide iPhone App Store data. Overall the U.S. actually had one of the smallest ratios of free to paid downloads for popular apps — its 15x ratio was dwarfed by countries like China and Saudi Arabia, which report free to paid download ratios of more than 100x.

Although the company declined to provide its own estimate of what percentage of app downloads are free, Distimo believes it is more than 89 percent reported by Gartner. Both companies agree however, that in-app purchases are driving the ratio of free to paid apps even higher.