Time, According to Our Independence

Apparently today is State Employees Day in North Carolina. I never knew such a day existed until our office manager brought in donuts this afternoon.
I looked up the official proclamation that Governor Easley made and found this interesting bit at the bottom:

"IN WITNESS WHEREOF, I have hereunto set my hand and affixed the Great Seal of the State of North Carolina at the Capitol in Raleigh this nineteenth day of February in the year of our Lord two thousand and seven, and of the Independence of the United States of America two hundred and thirty-first."

I've never heard of anyone counting dates based on the date of U.S. independence.
That's kinda cool. Unusual, but cool.