Where retirees can write to get information of special value to them

There are more than 30 million Americans over age 62, and the proportion of older people is growing every year. Also growing is the number and size of the many groups set up to bring together and work for this huge segment of the population.

The following is a list of some of the major national senior citizens groups. You can find out more about them by writing to the addresses listed. American Association of Retired Persons 1909 K Street NW Washington, D.C. 20049

Membership open to anyone over 50, whether retired or not. Members eligible for reduced life, health, and auto insurance, group travel discounts, adult education, and driver improvement courses. Membership is $5 a year; $12.50 for three years. m Service Corps of Retired Executives (SCORE) Small Busineess Administration 1441 L Street, NW, Room 100 Washington, D.C. 20416

Members include retired businessmen and women who volunteer their services to small businesses that need management counseling. m Retired Senior Volunteer Program (RSVP) ACTION Washington, D.C. 20525

Local chapters around the country help retired people find volunteer organizations that can use the retiree's talents and experience, helping him or her to become more involved in community life. m National Association of Mature People 2212 Northwest 50th Street Oklahoma City, Okla. 73112

Membership open to anyone over 40. Members eligible for reduced group insurance, group travel programs, educational programs, and other services. Membership is $7.50 a year; $15 for three years. m Elderhostel 100 Boylston Street Boston, Mass. 02116

A network of colleges and universities and some independent schools that offer resident, one-week programs for senior citizens during the summer months. Members reside on campus and can take a course or two (there are no prerequisites).