Android grew 15 per cent month-on-month in terms of ad impressions on Millennial Medias mobile ad network, according to the companys latest figures. 

Millennial has released its Mobile Mix stats report for the month of July, and Android now has a 61 per cent share of overall smartphone impressions. Apple has a 21 per cent share, while Windows Phone 7 grew 71 per cent month-on-month, but remains a bit part player with 2 per cent of the market. 

Apple remains the top device manufacturer on the network, but Samsung had a strong month, growing 28 per cent since June. Motorola, whose smartphone business was recently acquired by Google, is the 5th leading manufacturer on the network, and had three of the top 11 phones. 

Millennial notes in its report that smartphones are now the primary source of ad impressions. “Our first Top 20 Mobile Phones list featured a mix of feature phones and smartphones, including seven BREW devices, three Java devices, two BlackBerry and Windows Mobile devices, one Apple device, and one Google/Android device,” says the report. “In Q2 2011, our Top 20 Mobile Phones list consisted entirely of smartphones.”

Gamings dominance of the application categories delivering ad impressions to Millennial shows no sign of abating – indeed the company reports a 35 per cent increase month over month to a 29 per cent share of application impressions. 

Health and fitness apps saw notable gains in this space too, says the company. 

“Health & Fitness application impressions grew 13% month-over-month,” says Millennials report. “Within the Health & Fitness category, calorie counting and recipe applications accounted for two-thirds of the impressions in July.”

To download a free copy of the report, head to the research section of Millennial Medias website.