The article presents information on the impact of primary pension trends on retirement income in the United States. Most of the previous research has measured pension trends by the change in the number of plans and/or participants. These measurements may reflect the shift in employers' or in part, employees' preferences for pension plans. This is because retirement incomes can be affected not only by plan terminations and creations, which immediately change the number of plans and active participants, but also by plan alterations, which are not immediately reflected in those measures. This article employs a new measure of the shift from defined benefit to defined contribution plans that attempts to capture such changes in future retirement income, the distribution of employers' pension costs across plan types. It also compares results of the employer cost measure to those derived from previously utilized measures of the shift in primary plan types. The plan types examined in this article are defined benefit, defined contribution and 401(k) plans.