There is a lot of argument over this - some people suggest that if you have a bounce rate over 40% you have problems whilst others are either more relaxed or suggest that even a bounce rate of 20% is too high.
According to Google (watch the video at the bottom of this page) the average bounce rate for most sites falls in the range of 40% - 60%. If your site bounce rate is below 40% you are doing well and if it's above 60% then you definately need to find out why.
Bounce rates do however differ across sectors, from business to business and are also affected by the size of your site and a range of other factors. If you are using Google Analytics one of the best things to do is to opt in to their benchmarking programme and then using benchmarking statistics for your sector (e.g. for other non-profits) compare how your site is performing compared to the industry average for sites of a similar size. For example looking at recent UK data for non-profits in February 2009 the average sector bounce rate was just over 46% for smaller sites (under 250 pages).
