Piper Jaffray analyst Gene Munster attended Apple’s Worldwide Developers Conference last week and surveyed 45 developers on their operating system preferences. In a letter to clients — as reported by “Fortune” (http://macte.ch/jPXVO) — he found:

° Only 7% are also developing apps for the Mac, down from 50% in 2008.

° Nearly half (47%) write apps for Android, 36% for Research in Motion’s (RIMM) BlackBerry, 13% for Microsoft (MSFT) Windows Phone 7 and 7% for Hewlett-Packard’s (HPQ) WebOS.

° Asked which platform had the highest potential for future growth, none mentioned the BlackBerry, WebOS or Nokia’s (NOK) Symbian.

° Although 100% preferred iOS for ease of development and monetization, they did have some complaints, chief among them Apple’s “strict limitations” (38%) and the App Store approval process (11%).