Arrange the following compounds in order of decreasing rate of hydrolysis for $\text{S}_\text{N}1$ reaction:

(I) $C_6H_5CH_2Br$ (unsubstituted benzyl bromide)

(II) $p\text{-}CH_3C_6H_4CH_2Br$ ($p$-methylbenzyl bromide)

(III) $p\text{-}CH_3CH_2C_6H_4CH_2Br$ ($p$-ethylbenzyl bromide)

(IV) 2,4,6-Trimethylbenzyl bromide (mesitylmethyl bromide)