How much do Chicago teachers make?

Ezra Klein:

Luckily, we don’t have to guess, since CPS publishes median salary statistics (see page 198 in this pdf). As is often the case with stats like these, the median salary is below the mean: for the 2010-11 school year, the most recent year for which data is available, the median salary was $67,974, as opposed to the mean of $74,236 that year (as reported, pdf, by the Illinois State Board of Education). That mean is slightly different than the one reported by CPS because it relies on more recent ISBE data.
Some of that salary has to go to pension contributions. Teachers are required to contribute 9 percent of their salary to their pensions, and support personnel must contribute 8.5 percent, as opposed to 6.2 percent if they were part of the Social Security system. But the Chicago Public Schools system pays for 7 percent of the employee contribution. So the more relevant comparison is a 1.5 to 2 percent contribution for CPS employees compared to 6.2 percent for private sector workers paying Social Security tax. So the median after-pension income is $66,614, which a private sector employee on Social Security would need to earn $71,017 a year to make. So a median of $71,017 (or a mean of $77,560) is the most relevant number for comparing Chicago public school teachers to other workers.
What about the longer school day that Chicago Mayor Rahm Emanuel is implementing? The school day is increasing from five hours and forty-five minutes for elementary school and seven hours for high school, to seven and seven and a half hours, respectively. Isn’t an increase in hours of that scale effectively a wage cut, in per-hour terms?