Distribution of plan enrollment has not changed significantly over the last few years. PPO's, which have grown steadily in enrollment since 1996, enroll about one-half (54%) of covered workers in 2003. HMO enrollment, which dropped throughout the late 1990's, has stabilized, enrolling one-quarter of covered workers (24%).

• More than half of covered workers (54%) are enrolled in PPO plans, up from 46% in 2001 and 39% in 1999 (Exhibit 5.1).
  
• • PPO enrollment is particularly strong in the South (60%) and Midwest (61%) and in the mining, construc-tion, and wholesale indus-tries (60%), as well as in the transportation, communica-tions, and utilities industries (59%) (Exhibit 5.2).

• After declining in the late 1990s, HMO plans now enroll 24% of covered workers (Exhibit 5.1).
  
• • HMO enrollment remains higher in the West, where HMOs enroll 37% of workers (Exhibit 5.2).
  • Workers in fully insured firms are more likely to be enrolled in HMOs (30%) than workers in self-funded arrangements (19%). Conversely, workers in self-funded arrangements are far more likely to be enrolled in a PPO plan (62%) than workers in firms that fully insure (46%).