Humoresque calendar prints 1960s

I found a box of old calendars and prints in my grandpa's attic including 12 of these cartoon pin-up-type prints. They each measure about 8" by 11" and I think they must have went with a calendar, but there wasn't any corresponding pages with dates. Does anyone recognize these that could confirm they were part of a calendar? And if so, what year? They all say Humoresque at the top and have a McCartney signature. Thanks for your help!