Since 1935, the Gallup Poll has done a survey of Americans by asking an open-ended question -- What do you think is the most important problem facing this country today?
The New York Times has looked at those polls and charted the results (with the biggest blocks in the chart representing the most concern). The chart above shows the problems that worry Americans as Donald Trump starts his presidency. The charts below show the problems as Americans viewed them at the start of the last 9 presidential terms.
The newspaper has charts going all the way back to 1935, if you would like to see them. I thought it was interesting to see how the issues that worry Americans have changed over time. To see the rest of the charts you can go here.