Back to School by the Numbers

(CNN) -- It's back to school time. Starting dates around the U.S. vary by state and district: Some schools started on different dates in August, while others start this week. As we embark on the 2012-2013 academic year, here's a numerical snapshot of education in the U.S.

Grades K-12

54.7 million -- Number of students enrolled in elementary and secondary schools, both public and private, in the U.S. in 2011.

3.7 million -- Elementary and secondary school teachers working in U.S. schools in 2011.

$11,467 -- The estimated average amount a typical public school will spend on each student in 2012-2013.

31.8 million -- Number of children who received free or reduced price lunches through the National School Lunch Program in 2011.

3.4 million -- Students expected to graduate from high school in the 2012-2013 school year.

11.8 milllion -- Number of students who spoke a language other than English at home in 2010.

2.04 million -- Number of homeschooled students in 2010.

$83.8 billion -- Estimated amount to be spent on back-to-school shopping in the U.S. in 2012.

$688 -- Average amount parents will spend on back-to-school items for kids in grades K-12.

Post-secondary

21.6 million -- Number of students expected to be enrolled in colleges and universities in fall 2012.

12.3 million -- Number of female students expected to be enrolled in colleges and universities in fall 2012.

16 -- Percent of college students age 35 and older in 2010.

$20,100 -- Total annual cost of attending a public college/university in 2010, paying in-state tuition.

$39,800 -- Total annual cost of attending a private college/university in 2010.