Story highlights Bernie Sanders is only 7 percentage points behind Hillary Clinton nationally

A new CBS News/New York Times survey shows Clinton with a 48% to 41% lead over Sanders

Washington (CNN) Bernie Sanders is only 7 percentage points behind Hillary Clinton nationally, as the Democratic race continues to tighten.

A new CBS News/New York Times survey shows Clinton with a 48% to 41% lead over Sanders, a decrease from what was a 20 percentage-point gap only a month ago, when Clinton led 52% to 32%. The national poll follows other polls that show what appears to be a surging Sanders in both Iowa and New Hampshire.

The uptick for Sanders nationally comes almost entirely from younger voters: Sanders is up 60% to 31% with Democrats under the age of 45, compared with a 48% to 41% margin in his favor in December.

Among Republicans, the story remains the same: Donald Trump is trouncing the rest of the field nationally.

Trump leads with 36% support, according to the Tuesday survey, leading Ted Cruz with 19%. Following Cruz is Marco Rubio at 12%, Ben Carson at 6% and Jeb Bush also at 6%. All other candidates have less than 5%.

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