Evan Osnos writes this week about Kirsten Gillibrand, the junior senator from New York, and her tenacious approach to legislating. Today, Gillibrand and the other women of the Senate hold a record twenty seats. This is a dramatic shift: as recently as the nineteen-seventies, there was a five-year stretch without a single female member. This infographic shows the number of women serving in the Senate after each election cycle (the years on the left), starting with Rebecca Latimer Felton, of Georgia, in 1922. Felton was not elected but appointed by the state’s governor to fill a vacant seat; she served for only twenty-four hours.