By Dennis Crouch
The chart above is a histogram showing the age of utility patents at the time when an infringement complaint is filed. I used the Derwent LitAlert patent database and limited the search to only lawsuits filed Sept 16, 2011 - Sept 15, 2012 (this avoids false marking cases). I also excluded cases that were identified as declaratory judgment lawsuits in the LitAlert database. The data has some holes but it is roughly accurate.