From GTP, lowest AAII score is 12%

The lowest AAII (American Association of Individual Investors) bullish sentiment score ever recorded was 12.0%, which occurred on March 5, 2009.

This was during the depths of the 2008-2009 financial crisis, just days before the market bottomed on March 9, 2009. A low AAII bullish sentiment is often seen as a contrarian indicator, meaning extreme bearishness can signal potential market bottoms.