Every 52 weeks (6)
I believe the answer is:
yearly
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">every 52 weeks</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for yearly that I've seen before include "Perennial" , "Every 12 months" , "like circulation of the Sun?" , "A hundred times a century" , "Every tenth of a decade" .)