Since the creation of the S&P 500 in 1957, there have been 5 years with a decline of more than 10% each year
1973: 17.4%
1974: 36.7%
2002: 23.4%
2008: 38.5%
2022: 19.4%
The 5-year average is 27.08%
This is quite similar to the 27.6% shown above
The premise is that both sides ultimately sat down to negotiate again