Leaflet: The World Communist Movement: Yesterday and Today, 1983
Published by the Soviet English language magazine Socialism: Theory and Practice in 1983 this is an interesting overview of the size, state and demographics of the international Communist movement at the time.
By 1982 the number of Communist parties worldwide had grown from 1 in 1917 to 95 and the number of members of these parties had grown from approximately 400,000 to over 77 million.
In addition to a breakdown of the numbers of members of individual parties and in various global regions there are also numbers related to the class composition of these parties as well as the number of women members and other stats.
(Click on scans to enlarge)