Since $1951,$ the average temperature in Topeka has been increasing by $0\mathrm{.}3$F per decade. Accordingly, the average temperature increased by $\_\_\_\_\_\_$F between $1951$ and $2020.$

a$\mathrm{.}1\mathrm{.}8$

b$\mathrm{.}2\mathrm{.}1$

c$\mathrm{.}2\mathrm{.}7$

d$\mathrm{.}3\mathrm{.}0$