On trips to the USA over the last 5 years I'm AMAZED at how rare phones are. Until about two years ago I saw very few even among profesionals. I certainly saw none in use in the street. The last time I was over a year ago, they were relativly common amon the attendees of the conference I was at (hi-tech, hi-salary), but still none in the street.
In the UK, I'd guess 80% of the population has them, and that increases to about 99% of under 30's. EVERYONE has a phone.
Ian