NCIS, once the most-watched drama on TV, has seen a significant decline in ratings in its 20th season and the spin-off series NCIS Hawaii is also struggling. Season 20's fall finale attracted an estimated average of 6.4 million viewers, a sharp drop from previous years when the show consistently drew in 12 to 15 million viewers. This decline may be attributed to the absence of veteran actor Mark Harmon as Agent Leroy Jethro Gibbs. However, both NCIS and NCIS Hawaii remain the highest-rated network shows on Monday nights.
