Rank the following compounds in order of their expected reactivity toward $\mathrm{S}_{\mathrm{N}} 2$ reaction:
$$
\mathrm{CH}_{3} \mathrm{Cl}, \mathrm{CH}_{3} \mathrm{OTos}, \mathrm{CH}_{3} \mathrm{NH}_{2},\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCl}
$$