Source: http://blog.flurry.com

The data in this report is computed from a sample size of over 2,00 live applications and over 200 million user sessions tracked each month across Apple (iPhone and iPod Touch), Google Android, Blackberry, JavaME platforms.
With more than 75,000 applications in the App Store, consumers have a vast choice of alternatives to the applications they have already downloaded. And while discovery of new applications is a challenge for consumers, retaining users can be equally difficult for developers. To shed light on the kinds of applications that tend to be used over a longer period of time, Flurry studied user retention across 19 categories over a 90-day period. We monitored if consumers returned to use a downloaded application within 30, 60 and 90-day periods, as well as how frequently consumers used applications over those time periods. Flurry measures user retention by the number of users who downloaded an application, at any time in the past, and used that app within the last seven days.

Healthcare: Frequency  = 7 ; Retention = 30% .

Medical: Frequency  = 3 ; Retention = 40% .

More: “Mobile Apps: Models, Money and Loyalty” – http://blog.flurry.com/bid/26376/Mobile-Apps-Models-Money-and-Loyalty