What happened,
and under whom.
Any series against the governments in office across it. The same rule for every party. A change in office is marked where it happened; what caused what is not claimed.
Caveats, always: a government inherits the trend it starts with; most series respond to policy with a lag of months or years; recording practice and definitions change. This page shows what happened and when office changed hands. It does not say what caused what.