Oil prices are now at their lowest level in 12 years -- below $30 a barrel. That's great news for consumers, but not for the states that depend on oil tax revenues.

The falling price of oil, which has declined more than 60 percent since June 2014, has some states scrambling. With no end in sight, states that are more dependent on the industry simply can't replace the revenue by withdrawing from their substantial rainy day funds.

Oil, natural gas and mining account for about 10 percent or more of gross domestic product in eight states: Alaska, Louisiana, New Mexico, North Dakota, Oklahoma, Texas, West Virginia and Wyoming. Last year, total tax revenues in the eight states declined by 3.2 percent, according to a new analysis by the Nelson A. Rockefeller Institute of Government. In contrast, the remaining 42 states reported a 6.5 percent increase in total tax revenues.

Although most of these states tend to budget conservatively, the good years for oil had an impact on their finances.