Outgoing Starbucks Executive Chairman Howard Schultz told CNBC on Tuesday he doesn't think the stock market will "continue to grow at the rate it has between now and 2020."

Schultz, who acknowledged he's not an economist, also took aim at Donald Trump for using the stock market as an indicator of success in his presidency. "I think it's very wrong to use the stock market as a proxy for the U.S. economy."

The U.S. economy is strong, but Schultz gives former President Barack Obama the most credit for that. "I give President Trump some credit for that," he said in a "Squawk Box" interview.

Since the 2016 presidential election, the Dow Jones industrial average was up more than 35 percent as of Monday's close; the was up more than 28 percent; the was up more than 46 percent.

Trump has repeatedly taken credit for the U.S. stock market's record run.

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Trump has also been quick to point out when data point to a stronger economy.

On Friday, he came under criticism for tweeting about the May jobs report about an hour before the official release from the government.

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Schultz spoke with CNBC a day after he said he's stepping down from his role as executive chairman of Starbucks, effective June 26. He oversaw the massive expansion of the Starbucks coffee chain over the past 40 years.

Monday's announcement has fueled speculation that Schultz, an outspoken critic of Trump, could make a run for president in 2020. On Tuesday, Schultz told CNBC, "Let's see what happens."