Sen. Bill Nelson raised nearly $4.4 million in the second quarter, his campaign said Friday, a big sum for the Democrat but it's dwarfed by Rick Scott's $10.7 million haul.

Nelson now has $13.7 million in the bank, according to a release, which said he had 18,000 first-time contributors for the quarter, "highlighting the grassroots support and energy."

"Across Florida people are energized – knocking on doors, making phone calls and contributing to support this campaign because they know Bill Nelson has and always will put Florida first," said campaign manager Marley Wilkes.

"This record-breaking quarter with nearly 20,000 new supporters proves Floridians know Bill Nelson fights for them every day to protect Medicare and Social Security and keep protections for those with preexisting conditions to ensure they have access to health care and working to protect Florida's environment."

Florida's Senate race is the most expensive in the country, with $26.2 million already spent on TV, according to Advertising Analytics numbers reported this week by NBC News.