The stability of dihalides of $\text{Si, Ge, Sn}$ and $\text{Pb}$ increases steadily in the sequence:

In group 14, the stable oxidation state is $+4$. However, as we move down the group, the "Inert Pair Effect" becomes more prominent. The $n{s}^2$ electrons become increasingly reluctant to participate in bonding. Consequently, the stability of the $+2$ oxidation state increases down the group while the stability of the $+4$ oxidation state decreases.Order of stability for $+2$ states: ${\text{SiX}}_2<{\text{GeX}}_2<{\text{SnX}}_2<{\text{PbX}}_2$.For Lead, the $+2$ state is much more stable than the $+4$ state.