Hillary Clinton maintained a solid lead over Sen. Bernie Sanders (I-VT) in a national online tracking poll released by NBC News/Survey Monkey on Tuesday.

Clinton earned 51 percent support from Democrats and Democratic leaning voters, while Sanders earned 39 percent support, giving Clinton a 12-point lead. Clinton gained a percentage point from the tracking poll released last week, and Sanders’ support remained the same.

According to TPM’s PollTracker Average, Clinton leads Sanders 50.3 to 37.6 nationwide.

The NBC/Survey Monkey poll surveyed 3,154 registered Democratic voters online Feb. 1-7 with a margin of error plus or minus 2.4 percentage points.