Percentages are simply another way of expressing hundredths.
"Percent" means "out of a hundred."
So 1% = 1/100 = 0.01
10% = 10/100 = 0.10 = 0.1
20% = 20/100 = 0.20 = 0.2
43% = 43/100 = 0.43
Remember that 50% and 5% are very different:
50% = 0.50 = 0.5
5% = 0.05