Consulting the Codex…
RS3 · Skills · Activities · Quests
The Codex keeps its readings for 400 days, so you can go back that far, to the first day it read DisableChats.
Defence 86 → 90, 1.7m XP
Herblore 72 → 96, 8.7m XP
Prayer 77 → 95, 7.2m XP
Summoning 74 → 96, 8.5m XPWeakest area: Potions. Herblore 72 → 96, 8.7m XP. Quests need a public profile, so the quest checks are left out of the score.