Issues
#1+3 printings April 1972
#2 May 1972
#3 July 1972
#4 September 1972
#5 November 1972
#6 January 1973
#7+1 printing March 1973
#8+1 printing May 1973
#9+1 printing June 1973
#10+2 printings July 1973
#11+1 printing August 1973
#12+1 printing September 1973
#13+1 printing October 1973
#14+1 printing November 1973
#15+1 printing December 1973
#16+1 printing January 1974
#17+1 printing February 1974
#18+1 printing March 1974
#19 April 1974
#20 May 1974
#21 June 1974
#22 July 1974
#23+1 printing August 1974
#24+1 printing September 1974
#25+1 printing October 1974
#26+1 printing November 1974
#27+1 printing December 1974
#28+1 printing January 1975
#29 February 1975
#30 March 1975
#31 April 1975
#32 May 1975
#33 June 1975
#34 July 1975
#35 August 1975
#36 September 1975
#37 October 1975
#38 November 1975
#39 December 1975
#40 January 1976
#41 February 1976
#42 March 1976
#43 April 1976
#44 May 1976
#45 June 1976
#46 July 1976
#47 August 1976
#48 September 1976
#49 October 1976
#50 November 1976
#51 December 1976
#52 January 1977
#53 February 1977
#54 March 1977
#55+1 printing April 1977
#56+1 printing May 1977
#57+2 printings June 1977
#58+2 printings July 1977
#59+2 printings August 1977
#60+2 printings September 1977
#61+1 printing November 1977
#62+1 printing January 1978
#63 March 1978
#64 May 1978
#65 July 1978
#66 September 1978
#67 November 1978
#68 February 1979
#69 April 1979
#70+1 printing August 1979