9.5% quarterly decline results in 33% annual rate

Both in the US and Germany the GDP declined by around 9.5% in Q2 2020. The news also talks from an annualized rate of 33%. Which I did not understand until I realized that you have to apply the decline four times on the number that already has been lowered. As in:

100 * 0.905 * 0.905 * 0.905 * 0.905 = 67.079

Then it does make sense.