It can be written as an equation:
19 = x * 45 (x is the percentage we look for)
19 = 45x / : 45 (both sides)
x = 4,2222 (after rounding it to the thousandth)
It means that Raul had 42,222% of hits.
Doublecheck it:
45 * 42,2% = 18,9999 (the difference of 0,0001 is because of the rounding before, but it's correct)