The S&P 500 just crossed 3,200 for the first time ever, hitting its seventh round-number milestone of 2019, a year that has a good chance at being one for the record books.

With less than two weeks left in 2019, the S&P 500 is up more than 28%, about 1 percentage point away from 2013's gain of 29.6%.

If it exceeds that, it would then be the best year in 22 years, when the benchmark jumped 31% in 1997.

The S&P 500 has only posted only one down week over the past 11 as the easing trade tensions between the U.S. and China led to a rush into equities. The two countries reached a "phase one" agreement that includes some rollback of tariffs and more agriculture buying from China. Investors also shrugged off the impeachment of President Donald Trump by the House as chances are slim that he will be removed from office.

Based on the historic performance going back to 1950, the majority of December's gains in the S&P 500 have tended to happen toward the end of the month, according to Ryan Detrick, senior market strategist at LPL Financial. So if history is any guide, the market could have a shot at topping 1997's record.

"We still have time to believe in Santa," said Detrick. "December has been widely viewed as a strong month for stocks, with this year following suit so far."