Total viewers are almost entirely meaningless, at least in prime time.
CBS consistently promotes its 25-54 demo, but for the most part its also meaningless. They do this because its where they get the largest part of their audience.
Between the hours of 8pm and 11pm, ad buyers focus almost exclusively on two primary age demos 18-49, and 18-34. So many people get pissed that ad buyers basically ignore people under 18 and people over 50 during prime time, but they don't seem to understand the reason.
It's not because people 50 and older don't watch tv. They actually watch more tv then any other age demo. Its not that they don't have income.
Its because they can sell ads for 50 plus citizens throughout the rest of the day and the late night. Older americans (which include the vast number of retired citizens who don't have school, don't have jobs) can watch tv at 5am, 7am, 9am, noon, 2pm, 5pm, 11pm news, late shows, late, late shows. In fact, they do so in great numbers.
Ad buyers can reach that audience whenever they want to.
But for people 18-49, there is a rather small and narrow window where they watch tv and in large numbers, and that is prime time. Because they watch so little tv (in relation to the percentage of the total population), ad buyers pay a premium, a huge premium to get them when they watch in large numbers.
They can sell ads for products geared towards the older americans at so many different times of the day, ad buyers can't generate high rates per person of that age. But since 18-49 watch so little tv and watch in such a small window, ad buyers are willing to pay far, far more to ensure they reach that market.
Every show that has aired on Sunday has always had a larger audience then TAR, often with several million more in total audience, but with only one exception and for only one season no show on CBS Sunday has a larger audience in 18-49 viewers. That is why TAR is still around, and will continue to stay around.
And while its nice that TAR is winning its time period, that is really not relevant (historically TAR hasn't and again its been the one successful and stable primetime show on CBS Sunday). TAR isn't in renewal competition with shows from other networks, its in competition from other shows on CBS. As long as it continues to trounce the adult 18-49 demo of the other shows on CBS Sunday Tar will have a long future.