Group of 13 NAACP pinback buttons

"The earliest and smallest button reads simply 'N.A.A.C.P. 1920,' and is just 5/8-inch across. The others mostly read 'Member NAACP,' are about 3/4-inch across, and are dated 1948, 1950, 1951, 1954, 1955, 1956, 1961, 1962, 1965, 1968, and 1969. Another undated button an inch across reads 'NAACP Membership Drive.'"— https://catalogue.swanngalleries.com/Lots/auction-lot/-CIVIL-RIGHTS--Group-of-13-NAACP-pinback-buttons?saleno=2562&lotNo=154&refNo=779610