I think the number of people using it for errands, school, etc is 20% of the population
I don't really like the idea of 'cyclists' as an identity. We don't really have 'pedestrian' identities. Cycling is something that almost anyone can do - kids to seniors (if they keep it up when they are older), and having all this Critical Mass, specialized equipment, and things like that just creates an us vs them mentality. The focus should be on giving the average person more options and helping them feel safer.
The big thing to help recreational bikers and encourage them to use bikes for errands and other trips would be to have segregated lanes on those major arterial and high volume roads. Road - Parking - Bike lanes - Sidewalks..... Road-Curb-Bikelanes/Sidewalk on same level but different colours....Wide, different coloured bike lanes with priority at intersections also help. There are loads of different configurations besides the standards we seem to use here.
I went to Europe with my family last summer and had a good experience with that. My friend, brothers, and parents don't really bike too much at home except on separate paths, secondary country roads, and suburban back streets. Yet in Holland and Germany were all biking with confidence along major streets (urban and rural) with much more traffic than where we are from. The perception of safety really helps.... being separated from traffic makes you much more confident and safe, and the more people using these things the safer you feel. Plus there is a different attitude, where cyclists and drivers seem to understand each other better (from what my Dutch roommate tells me).
It's not unprecedented in Canada (this is in Montreal).
ps. Just in case you think I am some sort of bike crusader... I don't wear a helmet, I have a hand-me-down bike, never worn Spandex, don't go to Critical Mass etc... I have a drivers license and like using a car to get groceries, go far distances, and get places in a hurry. I just think that a lot more people would be using their bikes if we design our transportation system to make them safer... evidence already posted in this thread shows that this is the case, and that auto-oriented areas can be retrofitted to be more balanced.