If you had an investment and you consistently lost 5% of it per year for 6 years, how do you find the total percentage loss, without knowing the original investment?
Say that the amount of the original investment is $x$. Losing $5$% of it is multiplying it by $0.95$, so after the six years you’re down to $0.95^6x$, and you’ve lost $x-0.95^6x=\left(1-0.95^6\right)x$. As a fraction of your original investment this is
Now just simplify and convert to a percentage.