利用周末時間，設計一個定投計劃，看看過去25年的收益是否像說的那麽好（為了簡單，沒考慮分紅）
2000-01-01 started investing $1,000 per month on SPX, price was based on the first trading day of next month. For example, 2025-Jan, $1,000 was ordered at the closing price of 2025-02-03 since that's the first trading day of last Feb.
主要時間點：
2000-01-01 本金 $1,000 market value $1,000 started
2004-11 本金 $59,000 market value $59,766 從 .com 坑裏出來
2007-10 本金 $94,000 market value $123,200 before housing bubble crash
2009-03 本金 $111,000 market value $66,200 housing bubble bottom
2010-04 本金 $124,000 market value $122,300 從 housing bubble 坑裏出來, 從2000年到2010年，不考慮公司的contribution match, 這十年零收益還不到
2020-03 本金 $243,000 market value $532,500 before COVID
2020-04 本金 $244,000 market value $426,800 COVID
2025-03 本金 $303,000 market value $1.1 million
compared to GLD, since GLD was available from Nov, 2004, use $59,000 to be comparable to SPX.
2004-11 本金 $59,000 market value $59,000 started
2007-10 本金 $94,000 market value $57,500 before housing bubble crash
2009-03 本金 $111,000 market value $89,000 housing bubble bottom
2010-04 本金 $124,000 market value $122,300 從 housing bubble 坑裏出來
2020-03 本金 $243,000 market value $304,000 before COVID
2020-04 本金 $244,000 market value $305,000 COVID
2025-03 本金 $303,000 market value $631,000
