Peter's blog: It's official: developers get better with age. And scarcer.: "First interesting statistic is how users are distributed by age. On the graph we can see a textbook example of a bell distribution curve. I knew that with age coders tend to switch careers, but I was surprised to see the size of the drop. After the peak age of 27, number of developers halves every 6 to 7 years.
Second stat that I find most interesting is how Stackoverflow reputation relates to age. There is a near-linear increasing trend: the older the developers are the higher their SO reputation is. To see the reason behind this let's look at another graph:"