The big AM rockers of the 1960s also charted their most played records for promotional use. these unfortunately were also called "surveys" even though the term was totally misapplied. It becomes difficult if not impossible to research this topic. The basic idea is that a radio programmer would check one of the below boxes, make a comment and mail it back. Simple right? Radio survey cards, feedback cards... whatever you call them. I don't know when they started sending them out with the DJ promo copies shipped to radio. But as uncertain as it's beginnings are, it's end is equally unclear. The practice seemed to peter out in the 1980s. They were frequently tucked into the sleeves of 45rpm records. This one pictured is crom "Cross Country"
I can confirm that in the mid 1990s that a few independent promoters, were still at least mailing them. The follow up was non-existent and they did nto appear to be concatenated into any coherent data.
Some pre-recorded radio programs that were directly serviced to radio were also mailed with similar record surveys but their nature was different. Those programs had advertisers or underwriters and were seeking dedicated airtime and thus were not distributed as content, but as content providers. Still, it seems to be the last vestige of the practice.
Why did they die out? Mail surveys are expensive, even at 29 cents each, per prepaid buisness reply mail, that's multiplied by hundreds of singles and thousands fo stations. It adds up. One 45rpm single might now cost almost $600 in postage to service a single format. that does not include the cost of printing. Additionally the format has a lwo response rate, which leads to statistaically unreliable samples. It also suffers from a slow response rate. In an industry dropping new singles each week it's just impractical to wait weeks for the postcards to return.