I have never seen any publication numbers, but the 1971 catalog is far more frequently found up for sale than the 1972.
Just about any catalog 1969 and later is found to show up more frequently than the '72.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, AGITATION, CHAOS, TURMOIL, FIASCOS, AGGRAVATION, INSTIGATION, NUISANCE-ACTION, and HAVOC !