In the year $2020,$ a can of oysters cost $$3.$ In the year $2021,$ the same can of oysters cost $$5.$ If the consumer price index only included oysters, what would the inflation rate have been from $2020$ to $2021?$

$0\mathrm{.}666\%$

$33\mathrm{.}4\%$

$40\%$

$66\mathrm{.}6\%$