Business economists still think the economy will continue to grow for the next two years, but they again have scaled back their expectations for just how much.

The median estimate from economists surveyed by the National Association for Business Economics calls for gross domestic product growth of 1.5 percent this year, down from the 1.8 percent they forecast in June. The outlook for next year calls for 2.3 percent growth.

In addition, 81 percent of those surveyed said they don't expect the U.S. economy to peak until at least 2018.

The association notes that the September report, released Monday, represents the fourth-consecutive quarterly survey in which the participating economists have lowered their expectations for 2016 for GDP growth.

The group points to lower expectations for business investment as the main reason, but it also notes that worries about the outcome of November's presidential election are also weighing on expectations. Just over half of the economists surveyed said election uncertainty had a "modest negative" impact on their GDP expectation for this year.

The association added that 56 percent of those surveyed said they saw the possibility of a Hillary Clinton win as having a neutral effect on their economic growth expectations, while 60 percent said they thought the election of Donald Trump would have a negative effect.

On the bright side, the economists don't expect the reduced GDP expectations to carry over to consumer spending. The report's median forecast for growth in real personal consumption expenditures is 2.7 percent in 2016 and 2.6 percent in 2017.

Both predictions represent an increase of 0.1 percentage points from June numbers.

And the panel is now predicting flat corporate profits in 2016 — better than the median 2 percent decline projected in June. For 2017, they expect a gain of 4.2 percent.

The survey of 46 forecasters was taken between Aug. 8 and Aug. 25.