NPK varies ( many different studies ) but can average around 3-2-2 ( some with higher N up to 7% ) either way a non issue as it foes not burn plants. A large tablespoon of worm poop in say a 6” plant will make elements available for up to 2 months.
Worm castings have all the primary nutrients (nitrogen, phosphorus, and potassium) plants need. Castings also contain secondary plant nutrients (calcium, magnesium, and sulfur) and micronutrients like zinc, copper, manganese, iron, borax, and cobalt.