- 23December 23, 1979No events
- 24December 24, 1979No events
- 25December 25, 1979No events
- 26December 26, 1979No events
- 27December 27, 1979No events
- 28December 28, 1979No events
- 29December 29, 1979No 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.