A note to clients from Piper Jaffray's Gene Munster suggests that about 2% of Google's annual revenue comes from the iPhone.
The note highlights Apple's reasons for extracting Google from of iOS. We suspect that we'll hear about that next week at WWDC, if Apple announces an in-house replacement for Google Maps.
Here's what Munster says about Google revenue from iOS:
"We estimate Google will generate gross mobile revenue of ~$4.5 billion in 2012 with approximately $500 million coming from display and $4 billion from search. We believe iOS is likely to be the biggest or close to biggest po
