Hillary Clinton's advantage among likely California Democratic primary voters has slipped over the last five months, according to the results of the latest Field Poll announced Wednesday.

Less than half, 47 percent, said they would vote for Clinton, compared with 35 percent for Vermont Sen. Bernie Sanders and others finishing within the margin of error, while 14 percent are undecided. In May, 63 percent went for Clinton, compared to just 9 percent for Sanders. And in February, Clinton outdrew Sanders 73 percent to 10 percent.

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More than six in 10 (63 percent) said that a presidential run for Vice President Joe Biden, who has not declared for the presidency and was not included as an option, would be good for the Democratic Party. Just 22 percent said it would not be, while 16 percent had no opinion. But if he were to declare, just 15 percent said they would vote for him, compared with 31 percent for Sanders and 40 percent for Clinton.

And it appears that California Democrats are less enthusiastic about the prospect of Clinton being their nominee as well. In the last poll in May, 46 percent said their reaction would be enthusiastic, while 38 percent said they would be satisfied, 10 percent would be dissatisfied or upset and 6 percent had no opinion. In this poll, just 37 percent said they would react enthusiastically, while 42 percent said they would be satisfied and 20 percent would be dissatisfied or upset.

Among likely Latino voters, Clinton's pull is 52 percent, compared with just 22 percent for Sanders, who is tied with the former secretary of state at 43 percent among white non-Hispanic voters.

On a regional basis, Sanders performed best in the San Francisco Bay Area, drawing 38 percent to Clinton's 45 percent. In Los Angeles County, the Central Valley and other parts of Southern California, Clinton outperformed Sanders by double digits.

The state's primary is set for June 7, the second-latest date of every state and the District of Columbia that has announced its schedule. While the state carries the largest delegate haul at 405 plus 71 superdelegates, the race could be decided long before Californians head to the polls.

The poll was conducted in English and Spanish via telephone from Sept. 17-Oct. 4, surveying 391 likely Democratic primary voters, with a margin of error of plus or minus 5 percentage points.