Reuters/Baz RatnerHere is what you need to know. It's the 30th anniversary of the 1987 stock market crash. The Dow Jones Industrial average crashed more than 22% on October 19, 1987, making for the biggest one-day percentage drop in its history. China's GDP slows down a bit. Data released by the National Bureau of Statistics on Wednesday showed the Chinese economy grew at a 6.8% year-0ver-year rate in the third quarter, matching estimates but down from the second quarter's 6.9% print. UK retail sales post their slowest growth in 4 years.