I find it interesting that many of the IT/Engineering/Tech jobs have a high degree of connectivity to elementary/middle school teachers. So the high salaries are helping to balance out the crap salaries.
Like the previous post stated, this is likely just because there are many nurses and elementary school teachers. There was no statement that the graph corrected for this.
reminded how 20 years ago a school principal wife of an older guy in our IT department made sure that all unmarried/unattached guys from the department attended the Women's Day party (Russia) at her school :)