how do you convert 12.55 to percent? i get 1,255% is that correct? or should it be 125.5%?

If the 12.55 is a decimal, then .1255 is the percent. Per Cent means "per 100".

the math problem asked me to find the percent increase of the population in africa from 1950 to 2000. the answer i got was 12.55, now how do i write this as a percent; is it 1255% or 125.5%?