Washington (CNN) An energized Democratic base is translating into a clear fundraising advantage for the party's House candidates in this year's midterm elections.

The latest sign came in Federal Election Commission data filed last week showing that Democratic challengers outraised Republican incumbents in more than two dozen contests that made CNN's Key Races list.

The breakdown: six Republican seats currently rated as Toss-Ups, eight ranked as Lean Republican and 11 Likely Republican races.

One seat that stands out: New York's 22nd Congressional District, where 39-year-old Assemblyman Anthony Brindisi not only raised nearly $100,000 more than GOP Rep. Claudia Tenney, he also closed the year with roughly $18,000 more cash on hand. That seat moves from Lean Republican to Toss-Up.

The money momentum has also helped fuel Democrats who are seeking re-election in potentially tough districts. California's Rep. Ami Bera is no stranger to tight races, winning re-election last year by just 2 points. But he has nearly $1 million more in the bank than Republican Andrew Grant -- an edge that shifts his race from Lean to Likely Democratic.

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