Key (not everything below is exact, but it's an okay guideline)
1-20 - Silent landmarks
22-26 - pre-code horror
27-38 - Classics
39-42 - Val Lewton
43(ish)-52 - Noir
53-57 - Gangsters
58-69 - Hitchcock
70-74 - Sturges
75-77 - Lubitsch
79-83 - Ealing Studios Comedies
84-86 - William Wyler
87-92 - Billy Wilder
93-105 - Nihilistic 1950's westerns
106-122 - 1950's Hollywood classics
123-127 - Italian's transition out of Neo-realism
128-136 - French pre-new wave
137-144 - Japanese classic era
145-147 - Bergman
148-171 - 1960's - The last hard push of a dying studio system
172-180 - French New Wave
181-185 - Buñuel
186-188 - Yakuza
189-198 - Spaghetti Westerns
199-207 - 66-67 Rumblings before the New Hollywood Era
208-294 - New Hollywood (some foreign interspersed)
295-323 - Sci-Fi, horror, B movies and Italian&HK schlock
324-370 - Transition between eras
371-377 - Epics
380-445 - Essence of the 80s
446-451 - Hong Kong
452 onward - Studio and Indies side by side (plus foreign)