Use the following information to answer question 19-21.
In the baseball World Series, the American League champions play the National League champions. The first team to win 4 games wins the Series. The table below gives the year of the Series, the winning team's league (A for American and N for National), and the number of games that Series lasted. For example, the 1980 World Series was won by the National League team and lasted 6 games. The table includes the World Series from 1980 through 2000, except for 1994. In 1994, the World Series was not played due to a players' strike.
19. The National League won about what percent of the 20 World Series listed in the table?