A total of 50 goals were scored, so the relative frequency is found by dividing the number of goals by 50, or, equivalently, multiplying by 0.02.
Then your table becomes ...
[tex] \begin{array}{ccc}\text{data}&\text{freq}&\text{rel freq}\\1&8&0.16\\2&3&0.06\\3&12&0.24\\4&9&0.18\\8&11&0.22\\10&7&0.14\end{array} [/tex]