code: public static double toAnnualReturnFromGrowthRate(double growthRate, CalendarDateUnit growthRateUnit) {
          double tmpGrowthRateUnitsPerYear = growthRateUnit.convert(CalendarDateUnit.YEAR);
          return PrimitiveMath.EXPM1.invoke(growthRate * tmpGrowthRateUnitsPerYear);
      }
docs: AnnualReturn = exp(GrowthRate * GrowthRateUnitsPerYear) - 1.0
  
  @param growthRate A growth rate per unit (day, week, month, year...)
  @param growthRateUnit A growth rate unit
  @return Annualised return (percentage per year)