I remember the Times did a story about every state's tax structure. If remember every single state had a regressive tax overall, but Washington was either the worst or close to it. Lots of liberal states were toward the bottom because they all have excise taxes on alcohol, cigarettes, sodas, etc.
Washington is the most aggressively regressive state there is. There is no state income tax. Not only that, but city taxes are all consumption based, too. The birth center's city taxed us on the computer equipment we bought even though we didn't buy it in the city. What will blow your mind is that the state taxes are actually less than California's, and California also has about a 10-12% income tax, yet California's services are a good order of magnitude worse than Washington's because most of the money just goes to graft and corruption. They literally have double the budget per person and provide about a third of the services or less. My unemployment benefits in WA state are more than double what they are in CA.