ComScore recently issued smartphone numbers for May and the report sheds light on the market share held by the top mobile firms. One key fact that came from the most recent report is that Microsoft is losing market share significantly in America.

Microsoft's share of the mobile phone market has dropped a massive 35% since it released Windows Phone 7 last year. Smartphones running Windows Phone 7 made up only 9% of all smartphones sold when it launched, and as of May, the percentage is down to 5.8%. Microsoft is undoubtedly holding out hope that Mango will turn things around and the deal with Nokia will kick off when Mango lands putting more smartphones onto the market.

There is also speculation that some of Microsoft’s legal suits and patent licensing relating to Android devices are also carrying stipulations that the makers build more Windows Phone 7 handsets. 

RIM was above Microsoft in the ratings with 24.7% of the market in May. The last place finisher beneath Microsoft was Palm with 2.4% of the market. Only Apple and Google grew market share with Google holding 38.1% of the market and Apple holding 26.6%.

Microsoft's CEO Steve Ballmer admitted that Windows Phone 7 sales have gotten off to a rocky start. He said, "Phones, we've gone from very small to very small, but it's been a heck of a year. And you're going to see a lot of progress in that market competitively as we move forward."