The abortion rate for unmarried women and teenagers is dropping, the federal Centers for Disease Control reports, but the proportion of black and women minorities going to a legal clinic is increasing.

The proportion of women obtaining an abortion in their state of residence also is increasing, from 89 percent in 1975 to 93 percent in 1983. It has remained at about 92 percent since 1984, the CDC reported.These and other findings are outlined in the CDC's latest abortion surveillance summary that includes the years 1986 and 1987, the latest time period for which figures were compiled. The CDC compared the abortion statistics for those years with the numbers and percentages it collected between 1972-1985. The federal health agency first began it abortion surveillance in 1969.

According to the CDC, 1,353,671 American women obtained legal abortions in 1987, a 2 percent increase over the 1,328,112 reported to the agency in 1986.

The national abortion rate decreased from 24 abortions per 1,000 women ages 15-44 in 1985 to 23 per 1,000 in 1986 and increased again to 24 per 1,000 in 1987.

But the CDC acknowledged that its figures may be on the low side.