Among Floridians who selected a plan, what percentage are between the ages of 18 and 34?

The percentage of Floridians who selected a health insurance plan under the Affordable Care Act and are between the ages of 18 and 34 is 27%. This age group represents a crucial demographic for insurance companies, as younger individuals often have lower health care costs yet are essential for ensuring a balanced risk pool and keeping premiums stable.

This statistic is significant because it highlights the participation rate of younger individuals in marketplaces created through the ACA, emphasizing the goal of extending coverage to a wider range of people. Understanding the enrollment demographics can help policymakers assess the success of outreach efforts and determine how to attract more participants from different age brackets.

The other options, while reflecting percentages that may appear plausible, do not align with the reported data for this particular age group in Florida's ACA marketplace.