I'm sympathetic to your point, but you can't really make this comparison, because it's apples-to-oranges. The set of jobs in each set is quite different. For example, there are few farmers in the government employ.
However, we can still reach interesting conclusions from the data. For example, I would expect that regardless of the salary of the job, benefits such as healthcare insurance would be fairly constant for employees anywhere, and that in the private sector, healthcare is probably the single largest chunk of benefits. With this observation, we'd have to conclude that whatever salary you're making, the government is throwing in a pretty significant amount of extra value into their employee's benefits, whatever that employee's job might be.