Example: Mr. C reaches age 62 in January 1981 and becomes entitled to old-age insurance benefits in April 1981. He had no social security earnings before 1951 and his year-by-year social security earnings after 1950 are as follows: Mr. C's elapsed years are the 30 years 1951 through 1980. We subtract 5 from his 30 elapsed years to find that we must use 25 benefit computation years in computing his average monthly wage. His computation base years are 1951 through 1980 which are years after 1950 up to the year he reached age 62. We will use his 25 computation base years with the highest earnings to compute his average monthly wage. Thus, we exclude the years 1951-1955. The year 1981 is not a base year for this computation.

We total his earnings in his benefit computation years and get $236,000. We then divide by the 300 months in his 25 benefit computation years, and find his average monthly wage to be $786.66 which is rounded down to $786.

The primary insurance amount in the benefit table in appendix III that corresponds to Mr. C's average monthly wage is $521.70. The 9.9 percent and 14.3 percent cost of living increase for 1979 and 1980, respectively, are not applicable because Mr. C reached age 62 in 1981.

The average indexed monthly earnings method described in §§404.210 through 404.212 considers all of the earnings after 1950, including 1981 earnings which, in Mr. C's case cannot be used in the guaranteed alternative method. Mr. C's primary insurance amount under the average indexed earnings method is $548.40. Therefore, his benefit is based upon the $548.40 primary insurance amount. As in the guaranteed alternative method, Mr. C is not entitled to the cost of living increases for years before the year he reaches age 62.