Showing daily action of the 2018-2022 S&P 500, adding more detail of market action, seems pretty interesting to me. The S&P 500 is a weighted index representing the total capitalization value of the 500 largest U.S. companies. Then all of the S&P 500 Index mutual funds track it with similar percentage numbers (less fund fees).   ( A good S&P 500 graph )

The market goes up and down every day. So don't sweat the small stuff, think long term, but this table does show the past S&P 500 action. It can be volatile and has some bad times, which are "lost time" for earnings, but it always recovers, and overall performance is good and certainly worthwhile.

• 2017 S&P 500 Index closed at 2673.61, up 19.42% for the year.
• 2018 was Not a good year. December 24 was down 20%, with the year ending still down at -6.24% (not including the 2% dividend). But it recovered (7 months between the adjacent record highs). Still 19 record highs in 2018.
• 2019 had a slow start (recovering from end of 2018), but then 35 record highs with 28.88% year end gain.
• 2020 was the March pandemic crash (-34%). But it recovered (6 months between the adjacent record highs), not bad at all. 33 record highs and +16.25% year end gain (18.37% Total Return, including the dividends).
• 2021 was a great year, 70 record highs (to 4793.06) and 26.89% year end gain (28.66% Total Return).
• 2022 was awful, the painful inflation (to a 40 year high) self-imposed by the vast government spending of Trillions of give-aways. The U.S. had become self-sufficient on oil, but then the self-imposed current federal restrictions on U.S. oil production now requires importing oil again (which inflation affects all goods due to chemicals and/or transportation). The unbelievable open border and crime increase are huge worries piling up now. It all seems so unimaginable, but sadly it was real. The S&P 500 Index had only one new record high in 2022, which was on the very first market day of 2022. And then none for two years.
• 2023 was a different story. The recovery was trying, but the government obstacles were still in place. Market ups and downs, with big ups for the largest growth stocks, but many good companies are still well down today, with even worst negative growth than even 2022. The S&P 500 bottom was down 34% on 12 Oct 2022. Now there is much recovery for some growth stocks but very little yet for many others. But the market has always recovered, and the election should fix things again. Don't miss the gains coming in that recovery.
• 2024 was more of a normal good year, most very serious problems still there, but better than average market earnings, with new record highs again. 2025 can implement all the solutions again.

Annualized Return % requires all whole years. So including the incomplete current year numbers assumes the final year end is at today's price, which ruins the accuracy of the Annualized Return %. Annualization includes the long-term compounding of multiple whole years, and is a hypothetical number computed to be AS IF the SAME final gain result instead resulted from a Fixed equal gain, same every year (like bank interest). It didn't happen quite that way, but the final result is the SAME. This Annualized gain rate purpose then allows meaningful comparisons in the same time date period, and it computes the fixed gain rate that matches the same market compounded result. It hides any volatility during the years, computing a smooth path that would give the same gain result in the same time.

Speaking of comparisons, see 140+ individual stock and fund performance histories compared (any spans within 2014-2024 years, of Total Return %, including any dividends).

The gains in this next table are from the daily S&P 500 Index closing values. All numbers here are just the daily prices, so any dividends are not included here. The opposite in fact, unless reinvested, each dividend would be a withdrawal which is then subtracted from the stock price, dropping the price and investment value equally. However dividend reinvestment puts it back and restores the previous value by adding new free shares to the investment, highly recommended because it adds hugely to future long term earnings. (See more detail of that).
See annual S&P 500 Total Return detail in a 50 year S&P 500 Calculator.

There are often 252 Market Trading Days a year (but 253 in 2020, 251 in 2023)

Color Legend of table below: