- 19April 19, 1981No events
- 20April 20, 1981No events
- 21April 21, 1981No events
- 22April 22, 1981No events
- 23April 23, 1981No events
- 24April 24, 1981No events
- 25April 25, 1981No events
A=ANNUAL
M=MONTHLY
Q=QUARTERLY
DISCLAIMER: THESE DUE DATES ARE SUBJECT TO CHANGE. WE WILL DO OUR BEST TO KEEP THIS CALENDAR UP TO DATE WITH THE EVERCHANGING DEADLINES. ANY STATE FILING DUE DATES ARE IN REFERENCE SPECIFICALLY TO THE WASHINGTON STATE DEPARTMENT OF REVENUE.