How can this never be negative some years? Maybe I didn't understood how the CAGR is calculated.
Discussion
I think it's annualized returns, not annual returns. Could be wrong though
Because it’s the Compound Annual Growth Rate. It smooths out all the yearly ups and downs into one average rate over the full time period. Some years can be negative, but CAGR won’t show that. It just shows the consistent rate that would get you from the start to the end value.

