It's a 26 episode documentary, each episode was 50 minutes long. The bulk of the documentary was shown in 1974. Only 9 of the 26 episodes were aired in 1973, leaving 17 to be aired in 1974. It should be treated as being 1974.
Edvard Munch [eligibility to be determined]
Straddles the line, but I'd say more biopic than documentary.
I really hope that many people will take the opportunity to watch The Great Ecstasy of Woodcarver Steiner.