that's actually not that unlikely. You have: 140 million * 10 grams * 10% * 0.01% You want: Definition: 14 kg one standard US envelope is

that's actually not that unlikely. You have: 140 million * 10 grams * 10% * 0.01% You want: Definition: 14 kg one standard US envelope is about 10 grams, and assume 10% of affected sign up for credit monitoring and 0.01% use your service to send the opt-out. you might even wind up with multiple bags! 140 million is a lot of SSNs.