The legislative history of the exemption is explicit that the exemption applies only to an employee who is employed “primarily” as an announcer, news editor, or chief engineer. Thus the Senate Report states: “The exemption is specifically limited to those employees who are employed primarily in the named occupations * * *” (S. Rept. 145, 87th Cong., 1st sess., p. 37). No specific rule can be established for determining whether in any given case an employee is employed “primarily” in the named occupations. Generally, however, where an employee spends more than half of the hours he works in a workweek in a named occupation, he will be considered to be primarily employed in such occupation during that workweek. The answer will necessarily depend upon the facts in each case.