Pay very close attention to the advertisers on CBS’ “Blue Bloods” this week. Think pharmaceuticals and estate planning.

The CBS drama stars Tom Selleck (pictured with CBS CEO Leslie Moonves), and his fans turned out in abundance. It’s just that the actor’s fan base — as we’ve seen with the terrific “Jesse Stone” movie series — tends to be, how to put this99673_D1287b_e delicately, old. Like, Fox News Channel old. Just ask my mom.

Another network was kind enough to run the numbers on the breakdown of the program’s audience, which totaled an impressive 13 million viewers but delivered a mere 2.2 rating among adults age 18-49.

By way of comparison, “Glee” totaled 12.5 million viewers and a 5.6 rating among adults 18-49 last week, while “Modern Family” came in at 12.7 million and a 5.1, respectively.

Here’s the money figure: 76% of the “Blue Bloods” audience was age 50 and over, and nearly half of that was 65 and up.

Fairly or not, from a sales standpoint, that means CBS will be hard-pressed to cash in on the show’s otherwise-outstanding gross tune-in levels, which are even more remarkable given that it aired at 10 p.m. on Friday.

But come on, guys. Be creative. There ought to be some way for the sales department to cash in on all those eyeballs. For starts, older people vote in disproportionately high numbers, so this show ought to cash in between now and the midterm elections.

A friendly word of advice, however: None of the characters should be allowed to clap during the program.