The average annual return on long$-$term corporate bonds during the period from $1926$ to $2020$ was $\_\_\_\_$ percent.

The average annual return on long$-$term corporate bonds during the period from $1926$ to $2020$ was $\_\_\_\_$ percent.

$5\mathrm{.}2$

$7\mathrm{.}9$

$3\mathrm{.}8$

$6\mathrm{.}5$

$8\mathrm{.}4$