Note that the 36.5 million viewership number is the "total" viewership, not the average like most every other number you read on our site. It is the number of people that watched any portion of the race (likely a minimum of a few minutes, but not specified).
via press release:
WHEN THE SMOKE CLEARED,
THE 2012 DAYTONA 500 IS MOST-WATCHED IN FOX HISTORY
Historic Monday Night Running of the Great American Race
Captivates 36.5 Million Viewers
Daytona 500 Powers FOX to Primetime Win Against Strong Competition
New York & Daytona – It took 36 hours to complete from its scheduled start time but fans won’t soon forget the 2012 Daytona 500 and the dramatic events delivered for FOX Sports.
For the first time in the race’s 54-year history, rain postponed Sunday's 1:00 PM ET start until 12:00 PM ET Monday with continued showers in the afternoon delaying the green flag until 7:00 PM ET.
A total audience of over 36.5 million Americans watched last night’s race, according to fast national ratings issued today by Nielsen Media Research, making 2012 Daytona 500 the most-watched in FOX history. The 36.5 million total viewers, a measure of the audience that saw at least a portion of the race, is +22% higher than last year's total audience of 30 million and +22% better than 2010's 29.8 million. Yesterday’s total audience is the second best ever for a Daytona 500 on any network behind 37.0 million viewers in 2006 on NBC.
FOX won the primetime night among Adults 18-49 and total audience figures, a significant achievement going up against original episodes of popular network programs like ABC’s The Bachelor, CBS’s How I Met Your Mother and NBC’s The Voice, which was -10% lower in the Adults 18-49 demographic last night than it did a week ago. The Daytona 500 on FOX posted a 4.6 and averaged 14.1 million viewers from 8:00 – 11:00 PM ET, making it FOX’s most-watched Monday night in 16 months, dating back to Game 5 of the 2010 World Series.
The 2012 Great American Race, which included a fiery crash caused when Juan Pablo Montoya hit a safety truck/track-drying engine and red flagged the race for over two hours, earned an 8.0/14 rating/share and averaged 13.7 million viewers. While down slightly from last year’s Sunday afternoon race that occurred without any significant delays, (-8%, 2011 Daytona 500 - 8.7/20), Monday night’s race was up +4% when compared to the 2010 event (7.7/16), which saw lengthy delays for pothole repairs to the track.
Ratings for the 2012 Daytona 500 grew gradually through the first two and a half hours, climbing to an 8.2/12 (14.2 million viewers) in the 9:30 half-hour when the Montoya wreck occurred. Ratings grew further at 10:00 PM, peaking at an 8.8/13 (15.1 million viewers.) When the epic race concluded, Matt Kenseth emerged as the winner, capturing his second Daytona 500 victory in four years.
FOX Sports delivered live coverage of the 54th Daytona 500 for more than 11 hours over the course of three days. The NASCAR on FOX crew started reporting on Sunday from the rainy Daytona International Speedway, bringing viewers live interviews, updates, predictions and analysis from 12:00 - 5:15 PM ET in the hopes of a window opening up for racing. FOX Sports produced nearly the entire five hours live, including interviews with drivers who came to the Hollywood Hotel prerace set and in their haulers, as well as NASCAR officials in the booth, only briefly going to a replay of the end of the Budweiser Shootout and clips from SPEED’s Top Ten Daytona 500 Moments. The team was back again at 7:00 PM ET the next night for the historic Monday primetime running of the Daytona 500. The never-before-seen fiery crash halted action on the track for more than two hours, but sent the NASCAR on FOX crew into overdrive interviewing 21 drivers. When FOX Sports signed off Tuesday morning at 1:00 AM ET, another six hours of live coverage was in the books. National ratings for Sunday’s programming won’t be available until Thursday March 1.
Top-rated markets for the Daytona 500 include: Greensboro (18.1/27), Jacksonville (18.1/27), Charlotte (16.7/26), Greenville (16.7/26), Dayton (16.1/25), and Orlando (16.0/26). Markets seeing the biggest growth from last year include: New Orleans (+46%, 7.3 vs. 5.0), Salt Lake City (+33%, 8.1 vs. 6.1), Ft. Myers (+30%, 15.5 vs. 11.9), San Antonio (+17%, 7.5 vs. 6.4) and Tampa (+17%, 12.5 vs. 10.7).