While these levies do yield state revenue they have failed in the past to influence the behaviour of economic actors to a significant extent, due to low rates, too many exemptions and poor monitoring and enforcement (Mehling, 2008). In the first instance, the lower end of each tax band was implemented, giving policymakers flexibility to increase the tax in response to changing circumstances. The National Assembly Standing Committee, the body responsible for setting tax rates and subsequently agreeing changes, can raise the tax without a repeated legislative process. However, computer-generated equilibrium (CGE) modelling in 2014 of the impact of EPT compared to a business-as-usual scenario suggests that carbon dioxide emissions were curbed by about 2 million metric tons in 2012 and 2013, or a decrease of about 1.7 per cent on business as usual (Huong, 2014).