Note that this is different for certain kinds of civil servants (so-called Beamte). A rule-of-thumb for a typical public entity is that about 10% of the budget go to health and pensions of those public servants (but the exact number varies substantially between different entities), with rising numbers.

There was a distant time where some bus drivers were also appointed Beamte but that practice was done away decades ago, so there are only very few such drivers left.