Table 1.

Transition from the gross sample to the final sample

	Observations	Workplaces
Gross sample	43832	9372
At least one employee without attritiona	36579	8875
For profit	31786	7931
Value added >0	30416	7812
Odd years	18381	7766
Small firms	7784	3870
Large firms	10597	4385

^aIn even survey years, employees who had a different employer or left his employer and did not have a new employer were considered as attrition