100 percent (3)
I believe the answer is:
all
'100 percent' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for all that I've seen before include "Comprising every individual one" , "Total" , "and 18: 'Sing through -- --' (carol)" , "and 16 Across and 23 Across: Even so" , "Avenue, walk or garden path" .)