[michtzik]

Yup, this inspires great confidence in the source.

> 10,109 ... left their jobs

> departures outnumbered new hires last year by a ratio of 11 to one

That means that there were ~919 new hires, and thus it seems that 10,109 minus 919 equals

> a net loss of 4224

It appears that the "11 to one" ratio is the average, across agencies, of each individual ratio. It's left as an exercise to the reader to determine whether that average has any meaning at all.