Google's Android platform is closing the developer monetization gap with Apple's iOS based on average monthly revenue.

The findings were detailed in VisionMobile's Developer Economics survey, which aims to track the mobile app economy. The survey, released Wednesday, queried 6,000 mobile developers. VisionMobile is a London-based research outfit.

Monetization data is a critical part of the mobile platform race. Today, developers prioritize iOS over Android despite the latter's market share. Money is a big part of that equation. It's also unclear in the Developer Economics study how much Amazon boosted the Android revenue figures with its e-commerce skin.

Aside from the revenue data, the global survey also noted that HTML5 is becoming a developer favorite. Fifty two percent of developers are using HTML5, up from 50 percent in the first quarter. That figure is behind iOS at 56 percent and Android at 71 percent. HTML5 is seen as the primary way to bridge platforms and developers are using the language to target mobile browsers. In addition, Windows Phone is stagnant among developers, but Windows 8 and BlackBerry 10 are garnering interest.

VisionMobile noted:

The largest share (38%) of HTML5 developers develop mobile websites with another 23% developing mobile apps, i.e. incorporating offline functionality and deeper browser integration. Hybrid apps, such as those produced by PhoneGap, account for 27% of HTML5 mobile developers. A minority of 7% of HTML5 mobile developers use platforms exposing native APIs via JavaScript, such as Firefox OS and BlackBerry 10. Last but not least, 5% of HTML5 mobile developers use a JavaScript-to-native converter tool like Appcelerator.

Intent is also a key item. Developers are showing interest in emerging platforms---even Firefox OS, which is just getting rolling. Windows Phone interest has dropped to be replaced by Windows 8, according to VisionMobile. Overall, Windows 8 and BlackBerry 10 appear to be garnering developer time and money.