This took place because football telecasts were protected contractually from interruptions in the wake of the infamous "Heidi Bowl" incident on NBC in November 1968. Despite the irregular scheduling, the program's hard-hitting reports attracted a steadily growing audience, particularly during the waning days of the Vietnam War and the gripping events of the Watergate scandal; at that time, few if any other major network news shows did in-depth investigative reporting to the degree carried out by "60 Minutes." Eventually, during the summers of 1973 through 1975, CBS did allow the program back onto the prime time schedule proper, on Fridays in 1973 and Sundays the two years thereafter, as a replacement for programs aired during the regular television season. It was only when the FCC returned an hour to the networks on Sundays (for news or family programming), which had been taken away from them four years earlier, in a 1975 amendment to the Access Rule, that CBS finally found a viable permanent timeslot for "60 Minutes." When a family-oriented drama, "Three for the Road", ended after a 12-week run in the fall, the newsmagazine took its place at 7:00 p.m. Eastern Time (6:00 p.m. Central) on December 7, 1975. It has aired at that time since for 44 years , making "60 Minutes" not only the longest-running prime time program currently in production, but also the television program (excluding daily programs such as evening newscasts or morning news-talk shows) broadcasting for the longest length of time at a single time period each week in U.S. television history. This move, and the addition of then-White House correspondent Dan Rather to the reporting team, made the program into a strong ratings hit and, eventually, a general cultural phenomenon. This was no less than a stunning reversal of the historically poor ratings performances of documentary programs on network television. By 1976, "60 Minutes" became the top-rated program on Sunday nights in the U.S. By 1979, it had achieved the #1 spot among all television programs in the Nielsen ratings, unheard of before for a news broadcast in prime time. This success translated into great profits for CBS, advertising rates went from $17,000 per 30-second spot in 1975 to $175,000 in 1982. The program sometimes does not start until after 7:00 p.m. Eastern, due largely to CBS' live broadcast of NFL games. At the conclusion of an NFL game, "60 Minutes" will air in its entirety and delay all subsequent programs.