On or before October 1, 1982, and annually thereafter, the department of health and human services shall attempt to reduce the number of children receiving assistance under title IV-E of the Social Security Act, who have been in foster care for more than twenty-four months, by the following amounts:

1. For the year beginning October 1, 1982, one percent of the number of children, in foster care for more than twenty-four months, and receiving benefits under title IV-A of the Social Security Act from July 1, 1979, through June 30, 1980;

2. For the years beginning October 1, 1983, and ending September 30, 1990, one percent of the maximum number permitted in the previous year; and

3. For all subsequent years, one-half percent of the maximum number permitted in the previous year.