[LEAPSECS] the inception of leap seconds

[Zefram]

Warner Losh wrote:
>Eg, would we really be worse off if we'd said 'there will be a leap second
>every 18 months starting Jan 1 1972?

That would be a pretty good result, but would anyone have picked that
rate of leaps in 1971?  That period happened to be a local maximum of LOD:
since 1966 the UTC frequency offset had been its highest ever at 30 ppb,
corresponding to a second every 386 days, and 1972 ended up having two
leap seconds.  A decree based on those few years would most likely have
dictated a leap second every 12 months, which would put DUT1 around +19
s in 2018 rather than the +3 s that you suggest.  Still good enough for
civil timekeeping (especially as a temporary deviation that would be
corrected by a new observation-based rule after a few decades), but not
as awesome as you made the scheme look.

-zefram