Dennis, what does each dot represent? I know there are many patents (including some I worked on) that had a very short pendency (e.g., < 2 years, some prioritized, others just were in less crowded art units and got a first action fairly quickly) with no priority claim. Is each dot one issued patent and you just ran this for a random small sample of issued patents? or is each dot the average of a larger sample (i.e., a particular art unit)? I am assuming the latter.

Measuring from the earliest priority claim can be misleading, as some continuation applications go back a very long time. While you excluded patents with the top .2% of patent term, continuation applications wouldn't receive any special PTA so the continuation applications that go back 10+ years are probably skewing the chart.

It might be interesting to run the chart again without considering priority claims.