Carolinas HealthCare System netted nearly $501.2 million last year at facilities across its system, a 302 percent increase from the $124.5 million it earned in 2011. The Charlotte-based health-care system owns, leases or manages 38 hospitals in the Carolinas. Net operating revenue grew 7.5 percent in 2012 to almost $6.6 billion. And operating income totaled more than $169.4 million, up 8.4 percent from $156.3 million in 2011. The Charlotte-based health-care system saw investment gains of nearly $262.1 for the year. It reported investment losses of $77 million in 2011.