Well technically the only time period in which episodes were
broadcast was 1966-71, since TV didn't exist in the other time periods!

But seriously, folks...
I don't know which edition of the Almanac you have, jeffrey. I've got the Millennium Edition and it seems to have more detailed information than you posted. Here's a chronological ordering I prepared of what's there.
1680 PTEpisode 1231 (1 episode)
1692Episode 1140 (1 episode)
1795-1796Episodes 366-461, 610, 623, 661-666, 885-886 (94 + 1 + 1 + 6 + 2 = 104 episodes)
1840Episodes 1109-1198 (86 episodes)
1841 PTEpisodes 1186-1245 (59 episodes)
Early 1890sEpisode 877 (1 episode)
1897Episodes 701-885, 922, 938 (182 + 1 + 1 = 184 episodes)
1949Episodes 270, 900 (1 + 1 = 2 episodes)
1966-1971Episodes 1-365, 461-661, 666-701, 815, 835-837, 873, 887-981, 1007, 1012, 1031-1032, 1035, 1052, 1070-1109, 1113-1114, 1198 (361 + 197 + 36 + 1 + 3 + 1 + 91 + 1 + 1 + 2 + 1 + 1 + 40 + 2 + 1 = 739 episodes)
1970 PTEpisodes 969-971, 975-1060 (3 + 86 = 89 episodes)
1995Episodes 1061-1070 (10 episodes)
The totals don't equal 1225 because some episodes take place in multiple time periods. Dreams set in different time periods aren't included in the list.