Between North Korea, global populist uprisings and nearly nonstop political uncertainty, 2017 was a year of turbulence—except in stock markets.

World stocks, as measured by the MSCI All-Country World Index, have risen every month this year, the first time in history that a calendar year has passed without a monthly decline. In fact, the index hasn’t had a down month since October 2016. It ended up 0.5% in December, and rose 21.8% over the course of the year.

Jeffrey Kleintop, chief global investment strategist at Charles Schwab, credited the strength to improving corporate profitability, tweeting, “Why have global stocks gone up every month so far this year? Earnings have too (both actual and expected).”

Chart courtesy Charles Schwab

See also:Why strong earnings aren’t just a U.S. story—in one chart

Recent gains in the U.S. have also been driven by the recently passed tax-reform legislation, where a cut in corporate tax rates is seen as providing an immediate boost to corporate profits, as well as by strength in the fast-growing technology sector.

Already the uninterrupted bull market has set records, some that are literally unbeatable, and can only be tied. 2017 will be the year with the fewest monthly declines in the history of the world index, which goes back to 1988. Before this year, the record stood at three monthly declines in a year, which has happened eight times. (On the other end of the ledger, the record for most monthly declines is eight out of 12, which last occurred in 2015.)

A similar record occurred in the U.S., where on a total-return basis, the S&P 500 SPX, -1.11% has risen for an unprecedented 14-straight months, though December. On a purely price basis, the S&P 500 has risen for nine straight months, its longest such streak since 1983. The Dow Jones Industrial Average DJIA, -0.87% also rose for nine straight months in December, its longest streak since 1959.

The world index was supported by broad gains across various geographic regions. There has been a jump of about 30% in emerging markets and a 23% rise in European stocks. The S&P rose 19.4%.

Read more:The S&P 500 has put another chapter in its historic march higher

The strength in the final month of the year wasn’t surprising, at least in the U.S. According to Asbury Research, December is “the seasonally strongest month of the year” for the benchmark index, based on data going back to 1957.

Historically speaking, the S&P rises an average of 1.47% over the course of the month, and it closes higher 73% of the time, “its highest incidence of a positive close for any month during this period,” according to John Kosar, Asbury’s chief market strategist.

Chart courtesy Asbury Research

Read more:’Tis the season: December lived up to its reputation for stock gains in 2017

Also: These are all the records stock indexes hit as with 2017 trading at a close

Nicholas Colas, co-founder of DataTrek Research, added that December is historically when the CBOE Volatility index VIX, -2.38% hits its lows for the year. “That may not happen this year—the November 2017 lows were 9.1—but if history is any guide (and we think it is) then US stocks are in good shape going into year-end.” The VIX has lost more than 20% of its value this year, and is currently trading around 11, almost half its long-term average.

Of the 56 lowest closing levels in the history of the VIX (since 1990), 47 of them occurred in 2017.

Trading was historically quiet this year. According to the WSJ Market Data Group, the absolute daily percentage change for the Dow was 0.31% in 2017. It was 0.3% for the S&P 500, and in both instances, that represents the smallest absolute daily percentage since 1964. For the Nasdaq Composite Index, the absolute daily percentage change was 0.44%, the smallest since 1989.

Read more:The last time stocks were this quiet was the year the Beatles went on Ed Sullivan

Among other records set this year, the S&P 500 has gone an unprecedented length of time without a pullback of at least 3%.

It is also closing in on the longest streak ever without a decline of 5%. According to Calamos Investments, which cited data from Bespoke Investment Group, the S&P has gone about 530 days without such a pullback, compared with the record 593-session streak than spanned from December 1957 to August 1959.

It has currently been more than 660 sessions since the S&P 500 saw a correction, defined as a 10% drop from a peak. It is a long way from beating this record, however, which currently stands at 2,553 sessions, a stretch lasting from October 1990 through October 1997.

Related:Stocks are still feeling the hangover of the dot-com bubble and the financial crisis

While the current expansion is the second-longest bull market in history, it has to last a few more years to take the gold. The current market, as measured from the financial crisis bottom in March 2009, has lasted for nearly 3,200 days. The longest in history—between December 1987 and March 2000—lasted for 4,494 days.

Opinion:Here’s why U.S. stocks will likely be higher in December 2018