I'm afraid it would be impossible to accurately compile the statistics you've requested. However, your children are still young and these statistics (from the U.S. Department of Education) may interest you. On average, homeschooled kids score one year ahead of their schooled peers on standardized tests. The longer the student homeschools, the wider this gap becomes. By the time homeschooled children are in the eighth grade, they test four years ahead of their schooled peers.
Of course, these results translate into better ACT (American College Test) scores. Research shows that high achievement on the ACT strongly indicates a greater likelihood of success in college. According to official ACT reports, homeschooled students repeatedly outperform publicly and privately educated students in the ACT assessment test. "What you can say about the homeschoolers is that homeschooled kids are well-prepared for college," says Kelley Hayden, a spokesman for ACT.
For more information about homeschooling and college, read And What About College? How Homeschooling Leads to Admission to the Best Colleges and Universities by Cafi Cohen.