I get my primary data from three main sources. pifeedback.com (which posts overnights, fast nationals, and final numbers), tvbythenumbers which does fast nationals as well as various press releases, dvr results, and posts duplicates of pifeedbacks final numbers., then sitsomsonline also provides final numbers.
Those three sources between them can get you data on all episodes back to the 2nd week of Season 10. And all are currently accessible.
Previous to that Marc Berman (who runs pifeedback's ratings site) also posts a daily column for media week. Previously a database was online that allowed you to look at past years data (it is no longer available). I managed to go through his full database before it was taken down (this had primarily Fast Nationals, but also some final numbers), and this provided numbers back to through most of season 5.
Episodes and years before that I went to hard copy going to the Los Angeles Times and looking through microfilm to get final numbers for all but two episodes of that TAR has. One I found from a magazine (but have not been able to confirm the number with another source, so I am leery of taking it as fact (its the opening episode of season 1), so much of the nations media was taken over by 9/11 that media reporting took a backseat.
Not being a facebook person I don't know what page the database on facebook is (I would love to see it). As for being able to find all the data on one place, well sorry but their currently isn't one.
http://forum.realityfanforum.com/index.php/topic,15505.0.htmlThis has most of the data I have on the first 12 seasons. And we have threads for ratings on the other seasons, but they are put together into a chart, just weekly postings based on the ratings as they come in. I would have updated the ratings archive, but I forgot how to post images to the thread. As I do have all the data saved and put together.
I think I will ask Peach how to post again and make the update the archive with the last three seasons.
pifeedback in addition to daily forums, have forums for many shows, including TAR and they do have for the last few seasons a ratings database. For the last year that data was taken (kind of surprisingly) from what is posted a sitcomsonline (as their viewer data is to decimal places and they are the only online source to post the adults 25-54 demo. The finals posted on their nightly forums at pifeedback goes to three decimal points.
One thing to remember is just looking at numbers really doesn't tell you a lot. You need to know what the competition is, what your lead in (as that also is a tremendous influence on what type of ratings you will get), and even what your lead out is (also influences just not as much).
Some examples. When Fox gets the overrun for football, it means most of the males viewing tv that night are going to be watching Fox. Are ratings should take a hit. With 60 minutes as are lead in we are getting the oldest audience in television as our lead in, we don't have a large overlap in viewers. But when football overruns during the Fall (and to a lesser degree Basketball during the Spring) 60 minutes numbers get a huge, huge lift (more then doubling their audience in adults 18-49, the only real number studios really care about) this means TAR has a much larger audience of younger adults that will watch. We get a huge push from those nights. And this last spring we saw better numbers in the last half hour then the first (which is actually a little unusual for us), this can be placed on the incredible (and baffling) performance of Undercover Boss (which also has a much larger younger audience then any show that has followed us since we moved to Sunday.
It's very easy to just look at the numbers of our show and try and find some internal reasons for the weekly changes. But usually (though not always) you can look at external forces and they cause much larger week to week changes.