Top to Crash…

Any ideas out there as to why the interim periods between market highs and start of crashes have been getting tighter progressively.

So just looking at some monthly data charts I see this:

In 1929, Aug 1929 high to Apr 1930 start, 8 months,

In 1987, Aug 1987 high to Oct 1987 start, 2 months,

in 2000, Mar 2000 high to Oct 2000 start, 7 months,

in 2008, Oct 2007 high to Jan 2008 start, 4 months,

in 2020, Feb 2020 high to Feb 2020 start, 0 months,

In 2022, Jan 2022 high, to Jan 2022 start, 0 months.