The chart above shows the perecent of patents that are awarded some patent term adjustment (PTA) at issue. I have highlighted a recent apparent downward trend that began around October 2010. Still, around 80% of recently issed patents have lengthened patent terms due to patent office delays that go beyond the statutory bounds outlined in 35 U.S.C. 154.
The chart below shows the average PTA award, again grouped by issue date. The break-point in early 2010 shows the impact of the Federal Circuit's Wyeth decision holding that the PTO had been under-calculating patent term. The average PTA award is now hovering around 600 days (20 months).