As we've seen before, percentages can always be written in decimal form. Here's some more detail:
100% is everything there is: the whole thing, for example. One whole is 1, so in decimal form: 100% = 1. Similarly 1% is one hundredth, so 1% = 0·01.
We can write any other percentage as a number in between:
Note that 33% is not quite one third, whilst 66% is not quite two thirds.