"Good Morning America" must have felt especially good Friday morning.

ABC announced Friday that its morning news program, "Good Morning America,"  posted 18-year highs against NBC's once-dominant "Today" show during the last week of August, showing its biggest gains against its morning-show rival in 18 years.

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In the week of Aug. 27-31, "GMA" came out on top of the morning heap in both the 25-54 demographic most important to news advertisers and total viewers, besting once-dominant "Today" by 152,000 viewers in the demo and 883,000 total viewers -- its largest margins of victory over its NBC competitor since 1994.

In total viewers, "GMA" swept the board that week, claiming victory all five days, and claimed a win in the key demo four of those five days.

The latest numbers represent a trend that's been growing this year. While "Today" has enjoyed a reliable Number 1 status in years past, 2012 has seen "Good Morning America" nipping at its heels and gaining ground. So far this season, "GMA" has cut its total-viewers gap with "Today" by 59 percent, and in the key demo by 51 percent.