Excerpted from Washington State Budget 101:

Most states have an income tax that makes their tax system more equitable across all incomes and better ensures public revenues keep up with population and economic growth. That means other states have been able to invest in their people and public structures, while Washington has fallen behind. Washington’s rank in K-12 spending fell from 34^th to 45^th compared to state personal income from 1998 to 2009, according to the U.S. Census Bureau.