ANSWER IS $21\mathrm{.}4$

PLEASE show me how to figure this out STEP BY STEP

Last year, some $34\mathrm{.}5$ million consumes bought at least box of graham crackers, but the Graham Cracker Association believes that there are $125\mathrm{.}5$ million potential buyers. Purity Grahams claims $11\mathrm{.}3$ million buyers last year, while Golden Graham Crackers claims $7\mathrm{.}4$ million buyers. Calculate PENETRATION SHARE for Golden Graham Crackers. $($Round your answer to the nearest tenth of a percent. Report $27\mathrm{.}5\%,$ for example, as $"27\mathrm{.}5".)$

EXACT SUBJECT IS MARKETING METRICS