I need a little help from anyone who has some reference material from way back. What year did the eligibility requirements drop from age 25 to 21. In a plan termination audit by the PBGC I was asked to provide an explanation as to why someone did not enter the defined benefit plan until 4 years after their initial employment date. I do not have census information for the early 1980's so I can only speculate that it had something to do with the change in eligibility requirements. This individual was only 20 when he was hired. I do not have a copy of the original plan document.