Chinese Friendship Store Poster of Coca Cola, 80's

Hi, i'm trying to determine how rare is this Chinese Poster of Coca Cola. I got it personally in a Friendship Store at Great Wall in 1987. At that time we were given free bottles of coke and I ask a guy for the poster that was fixed on the window, thinking that he had some spare. Surprisingly, the attendant decide to took of the poster from the window with a knife. The poster is made with a thick plastic, silk screen printing and the glue is thick too. Thanks for the help.