Bottomsup2000 -- Interesting the way in which some of us think about the subject -- haha but I do like the way ya think !!
However seen from an Australian perspective I'd say virtually impossible to even estimate as there as so many variables.......If for example one were to take the given US Population Statistic of 203 Million (1970 timeline ) then apply a conservative 10 % ratio of that figure, which equates to 20.03 Million "SINGLE" administrations of total population for that year one alone ....Capitalize that up to say 12 Given / received (one per month ) for that year & the figure is staggering ....Even at say 5% the figure is still quite something !!!
Then as Grace 1 mentioned there were those that never acknowledged or even discussed in conversation, either due to embarrassment or possibly for fear that their friends of that time may consider them somewhat weird ,we all know how kids can poke fun at others....The stories some Schoolyard days could reveal huh !!.
Add to that those that will never ever come forward ( let alone admit too ) for reasons only known to themselves --- Guess we'll never know...
Then there is those that have taken their final bow & left the planet !! -- R.I.P.
So just for the fun of it I applied a simple 20 year incremental population growth based on the law of averages at 2.65 Million, being a combination of both newborn & migratory intake residents per annum (impossible to calculate transients--no known statistics ) over that time span....
Beginning & including the stated year population of 150 Million :
1950 to 1955 inclusive >>163.25Million Pop.---10% applied for each & every year 93.975 Million.
1956 to 1960 inclusive >>176.50Million Pop.---10% applied for each & every year 85.600 Million.
1961 to 1965 inclusive >>189.75Million Pop.---10% applied for each & every year 91.505 Million.
1966 to 1970 inclusive >>203.00Million Pop.---10% applied for each & every year 98.850 Million.
So arriving at 369.930 Million "single" or one time only's (based on the 10% p.a. factor for each & every year) & considering Emom's figure of approximately 10 given / received per singular entity--- Now arrives at 3.69930 Billion "spread" over 20 years...mmmmmm !
Averaging out at 18.4965Million "special delivery's" per annum or 50,675.342 Per Day ..... Give or take--LOL.
No wonder you guy's had to build the "HOOVER" Dam..
Anyone care to "Work Out " the Quarts ??