- 18January 18, 1981No events
- 19January 19, 1981No events
- 20January 20, 1981No events
- 21January 21, 1981No events
- 22January 22, 1981No events
- 23January 23, 1981No events
- 24January 24, 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.