SP 500 熊市回測

平均跌幅約35%，極端一點可以去到50%(大肅條這次就不計了，下跌80%，大家都GG)，現在SP500 下跌了約30%。平均下跌的日子最快都要3個月，現在SP500 才下跌了1 個月，撈底仲有時間。

資料來源 : https://www.yardeni.com/pub/sp500corrbeartables.pdf

Peak Date	Trough Date	Peak Price	Trough Price	Percent Loss	Number of Days**
9/7/1929	11/13/1929	31.92	17.66	-44.70	67
4/10/1930	6/1/1932	25.92	4.40	-83.00	783
9/7/1932	2/27/1933	9.31	5.53	-40.60	173
7/18/1933	10/21/1933	12.20	8.57	-29.80	95
2/6/1934	3/14/1935	11.82	8.06	-31.80	401
3/6/1937	3/31/1938	18.68	8.50	-54.50	390
11/9/1938	4/8/1939	13.79	10.18	-26.20	150
10/25/1939	6/10/1940	13.21	8.99	-31.90	229
11/9/1940	4/28/1942	11.40	7.47	-34.50	535
5/29/1946	10/9/1946	19.25	14.12	-26.60	133
6/15/1948	6/13/1949	17.06	13.55	-20.60	363
7/15/1957	10/22/1957	49.13	38.98	-20.70	99
12/12/1961	6/26/1962	72.64	52.32	-28.00	196
2/9/1966	10/7/1966	94.06	73.20	-22.00	240
11/29/1968	5/26/1970	108.37	69.29	-36.10	543
1/11/1973	10/3/1974	120.24	62.28	-48.20	630
11/28/1980	8/12/1982	140.52	102.42	-27.10	622
8/25/1987	12/4/1987	336.77	223.92	-33.50	101
3/24/2000	10/9/2002	1527.46	776.76	-49.10	929
10/9/2007	3/9/2009	1565.15	676.53	-56.80	517
2/19/2020	3/16/2020	3386.15	2386.13	-29.50	26
			average	-36.91	343.9