A new study by Bank of America has quantified “how large the missed opportunity can be” for investors who try to time the market, according to a recent article in CNBC.

Analyzing data back to 1930, BofA found that if an investor sat out of the market for the 10 best days each decade, total returns would stand at 28%, compared to a staggering 17,715% return for the investor who endured the ups and downs.

When stocks plunge, a natural impulse can be to hit the sell button,” the article notes, but adds that the BofA study found that “the market’s best days often follow the biggest drops, so panic selling can significantly lower returns for longer-term investors by causing them to miss the best days.”

Savita Subramanian, BofA’s head of U.S. equity and quantitative strategy, said, “Remaining invested during turbulent times can help recover losses following bear markets—it takes about 1,100 trading days on average to recover losses after a bear market.”

The data also showed that any investor who was able to somehow call the ten worst days of each decade enjoyed astronomical returns— “to the tune of 3,793,787%.” It adds, however, “Given the difficulty of precisely calling peaks and troughs, the better bet is to simply stay invested.”