The performance indicator display a security's price performance from a reference day as a percentage. If the market is not available for the reference day, use nearest preceding day.
Note: The day must be given in GT internal format and must match the timeframe.
Example : GT::Indicators::PERF->new(["2001-09-22"]); GT::Indicators::PERF->new(["2001-09-22", "{I:Prices VOLUME}"]);