Until this year it had more viewers than Mad Men.
30 Rock also grew its audience its second year.
30 Rock never did as well as the network hoped, but Boss has been an unmitigated disaster.
And expectations were very high for Boss - after all you had the star of Frasier, a show that put up champion numbers for years.
Comparing viewership of a program on NBC with viewership on a pay-tier network like Starz is stupid. The networks can put on the worst junk (like the atrocious Lavern & Shirley remake) and pull in several million viewers for a half season or so.