Ray Dalio calls it one of the most powerful forces shaping economic conditions. It’s so potent that he and a team at Bridgewater Associates, the $150 billion hedge fund he founded, published a 61-page paper on it Wednesday.

The research is titled, “Populism: The Phenomenon.”

Dalio defines populism as “a rebellion of the common man against the elites, and to some extent, against the system.” Over the last year, it has become a tremendously influential force, he said.

He tallied the share of votes received by populist candidates in developed countries around the world to create an index. The chart, on the first page below, shows a spike in populism recently – the highest since the 1930’s.

You can read his entire investor note below.