0.5% bike to work and 6% walk to work. Interesting that the difference is so large, you'd think that so many more people live withing short biking range vs walking range. I wonder what the stats are for other continents.
I do both (walk + bus and bike) but it's a lot more walk these days even though it takes almost 2x as long as biking for me. The main reason is that the bike commute is uncomfortable and it feels pretty dangerous, even though it's not that far. This is a big problem in US cities: roads are designed and built for cars, while cyclists and pedestrians are an afterthought.
Safety is a big concern, and a place to safely store your bike (at home and at work) is another big one. I'd imagine lots of the walkers live in condos or apartments where storing a bike can be really tough.