Washington SSP 2017, 2018, 2019

The Washington SSP values for 2017-2019 were $40. I was not able to find an explicit table showing the values.

These are the 2011 values, where the payment was $46: https://www.ssa.gov/policy/docs/progdesc/ssi_st_asst/2011/wa.html
In December 2013, they decreased the payment from $46 down to $40. (https://www.dshs.wa.gov/sites/default/files/ESA/briefing-manual/2024Appendix%208.pdf#page=27)
In January 2021, they decreased the payment from $40 down to $38.25. (https://www.dshs.wa.gov/sites/default/files/ESA/briefing-manual/2022Other_Programs.pdf#page=72)