Two decades ago, he favored public aid for private-school students, but after losing the 1977 mayoral election he learned not to oppose teachers' unions.

Results were only slightly improved for private-school students, who had an overall average of 63 percent.

According to the State Department of Education, the proportion of public- and private-school students entering college peaked in 1970, at 72.4 percent.

In all, Mr. Donato, $6.7 million of the current school budget went to providing services to private-school students.

The cost may also account for the abundance of private-school students (almost three-quarters) and white students (all but a couple).

The point, he said, is that drug addiction can attack anyone, even a high-achieving private-school student from a solid, middle-class family in Kentucky.

The report found higher test scores among private-school students in fourth grade, but in eighth and twelfth grades, there were no significant differences.

The school board then voted to permit home- and private-school students to attend public school part time.

The private-school students were no more likely than the public-school students to be suspended or expelled.

In addition, Mr. Terte said, some private-school students travel to nearby public schools for remedial instruction.