The nutrition facts lists the bag at 13 servings of approximately 50 pieces per serving, which comes out to be 650 pieces total.  Yes I did actually sit down and count out each color, results below.  No I have no life.

Yellow – 140

Brown – 161

Orange – 368

Total – 669

Percentage wise that is:

Yellow – 20.9%

Brown – 24.0%

Orange – 55.0%

It looks like it is supposed to be a 1-1-2 ratio for yellow, brown orange.  Of course there is no way to be sure if that is the true ratio without a statistically meaningful sample size, but I am not going to count another bag.