The statutes of the United States relating to the federal income tax, as in effect on December 31, 2018, but without regard to federal income tax rates under 26 U.S.C. § 1, are hereby adopted for the purpose of computing the tax liability under this chapter. (Added 2001, No. 140 (Adj. Sess.), § 7, eff. June 21, 2002; 2001, No. 144 (Adj. Sess.), § 23, eff. June 21, 2002; amended 2003, No. 66, § 313; 2003, No. 152 (Adj. Sess.), § 24, eff. June 7, 2004; 2005, No. 14, § 13; 2005, No. 94 (Adj. Sess.), § 2, eff. March 8, 2006; 2007, No. 33, § 6, eff. May 18, 2007; 2007, No. 190 (Adj. Sess.), § 26; 2009, No. 1 (Sp. Sess.), § H.26, eff. June 2, 2009; 2009, No. 160 (Adj. Sess.), § 29, eff. June 4, 2010; 2011, No. 45, § 2, eff. May 24, 2011; 2011, No. 143 (Adj. Sess.), § 9, eff. May 15, 2012; 2013, No. 73, § 20; 2013, No. 174 (Adj. Sess.), § 5, eff. Jan. 1, 2014; 2015, No. 57, § 66, eff. Jan. 1, 2015; 2015, No. 134 (Adj. Sess.), § 11, eff. Jan. 1, 2015; 2017, No. 73, § 7, eff. Jan. 1, 2016; 2018, No. 11 (Sp. Sess.), § H.7, eff. Jan. 1, 2018; 2019, No. 51, § 5, eff. Jan. 1, 2019.)