How many packs of cigarettes is 20mg nicotine?

Excuse me, but I have a question regarding the relationship between nicotine content and the number of cigarette packs. If we consider 20mg of nicotine, could you please clarify how many packs of cigarettes that would typically equate to? It's important for me to understand the correlation, as I'm interested in the health implications associated with varying nicotine levels. Your insight would be greatly appreciated.