I had this same question, and this discussion answered it. But I figured I'd do the math, too. So, since there's 16 days in a month and 12 months in a year...
The game begins on 1772.3.1 the target date is 1776.6.6, so that's 4 years, 3 months, 5 days.
(16 x 12 x 4) + (16 x 3) + 5 = 768 + 48 + 5 = 821 days OR 1,642 day/night cycles.
(Since this post was posted 244 days ago, you only have 577 days left to go, yippie!)