In my area I would say there are more commuters than there were 5 years ago. Here are my reasons why I think so.

1. I work on a small college campus and there are twice as many bike racks than 5 years ago and all but one of those racks are typically full. I know at least a couple of the racks the bikes do get used becasue I know who owns the bikes. Many more faculty and staff ride than a few years ago and part of that is probabyl becasue of the very successful Employee wellness program.
2. There seem to be more bike consumers out there. In the past 5 years 2 additional Bike shops have opened in town. 1 vintage shop and another well established shop opened a new location. 1 shop closed 3 or 4 years ago, but another one opened a while ago to replace it the previous one was pretty new. Besides this bike flippers (including myself) are popping up all over and some of them move a ton of bikes. It seems like every couple months more flippers on on CL offering bikes to the public. There have been a couple of different community based bicycle programs either just starting up or really gaining steam to met the increased demand.
3. It seems like there are more people out commuting and alot of the people who buy bikes from me say thats what they are planning to use it for. A couple of years ago thrift stores got smart and put higher pices on their bikes and people are/were often paying them. They still have some good deals, but gone are the days when nothing was over $25 which is ok with me since the money goes to various charities.

Lincoln is a bike town (Over 70 bicycle sculptures scattered around) and a college town so we have alot of trails and bike routes and lanes are getting marked more all the time. Its pretty easy to get around using the bike trails.

In my experience $4+ a gallon got peope at least attempting to commute by bike. That summer I was flipping bikes and they were selling like hotcakes. Rarely did it take even 48 hours to sell a bike after posting it on Craigslist. it was not uncommon to sell a bike less than 10 hours of listing it. I had less competition then and was offering them for pretty reasonable prices, but it was crazy how quick they were selling. This last summer bikes sure weren't moving as fast as that summer thats for sure. =) $4+ a gallon for gas adds up for alot of people and I think it did get some people started riding their bikes and they stuck with it.