According to the operation of the lunar calendar, the Gregorian calendar calculation, but there is no completely fixed law, roughly 19 years to repeat once. A small number of years are not, mainly the result of the lunar calendar. So, 19 years to repeat, people's life expectancy according to the optimistic estimate live 80 years or so, can meet four times is not easy, congratulations to you this year met once.
After searching information, Mid-Autumn Festival and National Day on the same day in 1944, 1963, 1982, 2001. What's more, in 2020, the Mid-Autumn Festival falls on Thursday, October 1, in the year of the Rat, August 15. The next one won't be until 2031.