One hundred forty-three cases of fraud using mailed ballots over the course of 20 years comes out to seven to eight cases per year, nationally. It also means that across the 50 states, there has been an average of three cases per state over the 20-year span. That is just one case per state every six or seven years. We are talking about an occurrence that translates to about 0.00006 percent of total votes cast. Heritage Foundation.