New York (CNN Business) The next US presidential election is a year away. Although we don't know which Democrat will face President Trump next year, it's not too soon to start thinking about what the election will mean for investors.

History suggests that the market will be bumpy in the first half of 2020 but ultimately settle down once it's clear who the Democratic nominee will be. And after the election dust settles, it probably will be back to business as usual for Wall Street.

"Election years are full of uncertainty. Investment performance could be impacted in 2020, due to this uncertainty," said John LaForge, head of retail asset strategy for the Wells Fargo Investment Institute in a recent report. "Bonds and stocks have historically struggled in the first half of election years—then lifted later in the year as the cloud of uncertainty lifts too."

According to his report, the Dow has had an average return of 7.6% during presidential election years since 1900, and positive returns 70% of the time during those 30 occurrences.

Although a second-half market bump during the presidential election cycle may be the norm, these are hardly normal times.

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