Yes, they did take this information off the website for some reason ... I emailed and requested it - here is the response:
"Thank you for your email.
Our color blends were selected by conducting consumer preference tests, which indicate the assortment of colors that pleased the greatest number of people and created the most attractive overall effect.
On average, our mix of colors for M&M'S CHOCOLATE CANDIES is:
Each large production batch is blended to those ratios and mixed thoroughly. However, since the individual packages are filled by weight on high-speed equipment, and not by count, it is possible to have an unusual color distribution.