Ths SPDR S&P 500 ETF Trust traded higher by 0.7 percent on Thursday, but that should come as no surprise to investors paying close attention to the calendar. The Numbers According to Ryan Detrick, Chief Market Strategist for LPL Financial, Oct. 28 has historically been one of the best days of the year for the S&P 500 dating all the way back to 1950. In fact, Oct. 28 was the best day of the year for stocks until the market dropped 3 percent last year. The average gain for the S&P 500 on Oct. 28 has been 0.46 percent, making it the third best date on the calendar for investors. However, Detrick said the fun has historically not stopped on Oct. 28. Oct. 29 (+0.32 percent), Nov. 2 (+0.32 percent) and Nov. 3 (+0.41 percent) also have extremely strong historical returns. In fact, Oct. 28 marks the beginning of the …