Piper Jaffray senior research analyst Gene Munster said Friday that based on Apple’s announcement of 200 millions songs being downloaded from the iTunes Music Store so far, the company is selling approximately 5.5 millions songs per week, up from 3.5 to 4 million songs last quarter. Based on this run rate, Munster said in a research note to clients, he is expecting iTunes downloads in the December quarter to reach 68.5 million, up from his previous estimate of 52.1 million. He said that assuming 68.5 million iTunes downloads in the December quarter and 4 million iPod shipments, Apple would be averaging 7 iTunes song purchases per iPod. “If we apply this 7x ratio to our cumulative iPod installed base estimates through calendar year 2005, iTunes downloads for 2005 would be at 474 million vs. our current estimate of 256 million,” Munster said. The analyst is also looking for iTunes revenue to account for 3 percent of Apple’s total revenue in 2005.