Research In Motion has seen half of its share of the U.S. mobile platform market disappear in the past year, according to an analysis of the cell phone industry.

Comscore’s latest rankings of the U.S.’s largest cell phone market players shows the Waterloo, Ont.-based company fell from 40 per cent of the cell phone platform market in July of last year to slightly more than 20 per cent this July.

But the company’s share of the cell phone handset market was more stable, rising to 9 per cent of the U.S. market in July, 2011, from 7.6 per cent the same month a year earlier.

The largest beneficiary of RIM’s decline has been Google, whose Android platform has taken the cell phone world by storm in the past year. Android’s numbers are almost a mirror image of RIM’s, with its platform market share jumping from 17 per cent a year ago to 41.8 per cent today.

While Google rocketed from third place in the platform market to first, RIM fell from first to third.

The clear correlation between the rise of Android and the decline of the BlackBerry may have been the motivator behind RIM’s decision to release cell phones next year that are compatible with Android. It’s expected future BlackBerrys will continue to run on RIM’s own QNX operating system, but will be compatible with Android apps.

BlackBerry has been reporting disappointing earnings all year, as rocketing sales of Apple’s iPhone, as well as smartphones running Android, have eaten into the Waterloo, Ont.-based company’s sales.

RIM announced in July that it is laying off 11 per cent of its global workforce, or about 2,000 people.

The company also announced it is rolling out a streaming music service that will work through its proprietary messaging system, BlackBerry Messenger. The service will allow BBM users to share music amongst themselves and to download up to 50 songs to their devices.

Market observers suggested the move may be meant to overcome BlackBerry’s image as being “for work only,” while Android phones and the iPhone are perceived as being “for fun.”

Following the announcement earlier this month that Google is buying Motorola Mobility, speculation turned to RIM and the possibility that the cell phone maker could be rescued by a software company looking to partner with a hardware company. Observers have suggested that Microsoft could be that company.