In setting premiums for firefighters, rescue squad workers, and members of the National Guard, and their eligible dependents, the Plan shall establish rates separate from those affecting other members of the Plan. These separate premium rates shall include rate factors for incurred but unreported claim costs, for the effects of adverse selection from voluntary participation in the Plan, and for any other actuarially determined measures needed to protect the financial integrity of the Plan for the benefit of its served employees, retired employees, and their eligible dependents. (1981 (Reg. Sess., 1982), c. 1398, s. 6; 1985, c. 732, s. 52; 1991, c. 427, s. 5; 1997-468, s. 4; 1998-1, s. 4(e); 1999-237, s. 28.29(h); 2003-69, s. 2; 2004-124, s. 31.21(c); 2005-276, s. 29.31(e); 2007-323, s. 28.22A(m), (m1), (o); 2007-345, ss. 11, 12; 2008-107, s. 10.13(a); 2008-168, ss. 1(a), 2(a), (m); 2009-281, s. 1; 2009-571, s. 3(c); 2011-85, ss. 2.5(f), 2.10.)