To determine the percent of decrease we use the following formula:
[tex]\frac{Old\text{ value-New value}}{Old\text{ Value}}\times100.[/tex]Substituting:
[tex]\begin{gathered} Old\text{ value=33.57,} \\ New\text{ value=30.83} \end{gathered}[/tex]in the formula, we get:
[tex]\frac{33.57-30.83}{33.57}\times100.[/tex]Simplifying the above result, we get:
[tex]\approx8\%.[/tex]