The problem with this data is that everyone tries to keep thier tasks short. 1 day or less.
So then you are judging the description of the task. How much work is involved. But the descriptions will usually only have meaning in the context if the system.
- 'fix the bug with the pricing in this edge case'
Unless you know the system at the time, judging the size of the task is impossible. It could be 2 min or 2 weeks.
Ok we can look at projects rather than tasks. The descriptions will be easier to judge, but then we have to consider requirements change, interaction with other ongoing projects, quality of the final product etc. No two projects will be comparable and that information isn't available.
You'll probably find that on average projects take 1 quarter of a year because that's the financial reporting period and they are sized accordlingly