US population
US adult population
US adult population who will never get married
US adult population who will get married / 2 (it takes 2 people to a wedding)
US adult population who will get married more than once / 2
Add up the total number of weddings that current US adults are expected to go through in their life, divide by number of years spent in adult life
Bonus points: Trend for fewer / later marriage now than in your grand-parents' generation
