American Idol
Season eleven, however, suffered a steep drop in ratings, a drop attributed by some to the arrival of new shows such as The Voice and The X-Factor. The ratings for the first two episodes of season eleven fell 16-21% in overall viewer numbers and 24-27% in the 18/49 demo, while the season finale fell 27% in total viewer number and 30% in the 18-49 demo. The average viewership for the season fell below 20 million viewers the first time since 2003, a drop of 23% in total viewers and 30% in the 18/49 demo. For the first time in eight years, American Idol lost the leading position in both the total viewers number and the 18/49 demo, coming in second to NBC Sunday Night Football, although the strengths of Idol in its second year in the Wednesday-Thursday primetime slots helped Fox achieve the longest period of 18-49 demographic victory in the Nielsen ratings, standing at 8 straight years from 2004 to 2012.
For how many years was American Idol the top rated show on television? 
eight
For the first time in eight years, American Idol lost the leading position in both the total viewers number and the 18/49 demo, coming in second to NBC Sunday Night Football, although the strengths of Idol in its second year in the Wednesday-Thursday primetime slots helped Fox achieve the longest period of 18-49 demographic victory in the Nielsen ratings, standing at 8 straight years from 2004 to 2012.
American Idol