Washington residents paid $3,975 to attend the four-year public institution this year $622 less than the $4,597 charged for 2016-17.
Non-residents paid 10.5 percent more than residents this year, or $4,392. Their price tag was reduced 12.3 percent from $5,007 in 2016-17.
About 98 percent of the school's undergraduate population are Washington residents. And about 2 percent are residents of other states.
Data shows 56 percent of full-time undergraduates who started school in 2015-16 received student financial aid in some form. In all, 263 students received grants or scholarships totaling $1.47 million and 104 students took out student loans totaling more than $461,676.
Including all undergraduates, 2,092 students used grants or scholarships totaling $10.91 million. Another 823 took out $4.48 million in federal student loans.
Editor's note: A previous version of this story incorrectly described the cost of attendance, which includes both tuition and fees.