Looking back on some of my earlier projects, I noticed that UTs account for roughly 20% of my total code lines. I was wondering if anyone else has similar numbers for their unit tests? It seems to me that my numbers are a bit low, to achieve total test coverage I would expect over 50% (meaning more UT code then project code). On the other hand, I have yet to come across an application which actually achieved that kind of testing completeness other than certain open source libraries.
I know what the literature says, now can anyone come up with some real world numbers to back up my theory?