A new report on link rot on the blog of the social bookmarking service Pinboard:

• Remembrance of Links Past, by Maciej Ceglowski, Pinboard Blog (May 26, 2011).

Using a random sample of 300 URLs stored in Pinboard for each year 1997-2011 (based on the year the bookmark was created), Ceglowski says "you can expect to lose about a quarter of them every seven years."

Ceglowski also shows year by year lists and the raw data.

In my quick look: of the 47 .gov web sites checked over the entire period 7 were not found (status code 404) and 7 had internal server errors (status code 500) for a 29.7% link rot rate.

Hat tip to INFOdocket!