Public schools average about $12,700 per student.
Non-sectarian private schools are more expensive, running about $16,000 per student. That's about 20 percent of private school students.
Catholic and religious schools are cheaper, running from $7,000 to $9,000.
I don't have curves for overall tuition growth for private schools that go back as far as the public school numbers.
Private schools generally do better on achievment.
Source