This chart shows the evolution, as a percentage of the total number of pension plan members, of the prevalence of defined-contribution plans from 1991 to 2006 according to the size of the plans. The plan sizes used include small plans with 3 to 99 members; medium plans with 100 to 999 members; large plans with 1,000 to 9,999 members; and very large plans with 10,000 or more members. Across all plan sizes, the prevalence of defined-contribution plans increased steadily over the entire period. The most significant gains were obtained for medium-sized and large plans, going from 20.7% to 43.6% and from 8.0% to 23.1% respectively. Small defined-contribution plans went from 54.4% to 72.5% from 1991 to 2006. Finally, very large defined-contribution plans remain in the minority, going from 2.0% to 2.9% over the entire period.