Average Adult WizardStrength 400-500Speed 300-400Vitality 300-400Magic 4000-6000
Average Adult WitchStrength 300-400Speed 450-550Vitality 250-350Magic 4000-6000
VoldemortStrength : 180Speed : 692Vitality 287Magic ~400,000
DumbledoreStrength : 262Speed : 704Vitality 1,629Magic ~350,000
Voldemort's Strength and Vitality suffered from reliance on Horcruxes. Due to those Horcruxes and other dark rituals that boosted the strength of his magical vessel, the strength/potency of his magic has grown even greater then Dumbledores, but Dumbledore has the Elder Wand, which allows him to be boosted to a level beyond Voldemort's.
And Dumbledore's strength is as low as it is only due to old age,
Note, Average Witch and Average Wizard would apply to witches and wizards who complete their education and then are in a low stress environment where the growth of their magical vessel slows down to a drip. Obviously people like aurors, or disciplined sorts who keep training, can easily surpass these stats.
Mad-Eye MoodyStrength : 569Speed : 679Vitality 815Magic ~180,000