labor turnover,
1. the number of new workers hired in place of workers who have left their jobs.
2. the proportion of new workers hired to the average number of workers an employer has working for him: »
In many industries men are “hired and fired” freely, and a labor turnover of 100 per cent in a year has been known to occur (Emory S. Bogardus).
Useful english dictionary. 2012.