That ratings bump that NBC's Today show experienced during the two weeks of the network's coverage of the Olympic Games has certainly deflated rapidly. ABC's Good Morning America expanded its lead over Today last week by over 520,000 viewers, according to Nielsen Research. It also led Today on all five days of the week. Today did manage to eke out a win in the 25-54 age group, the demographic that advertisers prefer, but its margin of victory -- just 5,000 viewers -- is considered statistically insignificant. GMA has now topped Today in seven of the last nine weeks, with its only two losses coming during the Olympics.