Yet Another Gold:Silver Ratio Supporting Document

I came across this just now. It's a few years old, but I found the numbers interesting for Gold and Silver trading. Can anyone explain this? Historically I know the number has been around 1:10 (Gold:Silver) to 1:16 or thereabouts. This seems spot on...
http://hsgac.senate.gov/public/_files/052008Masters.pdf
Bottom of Page 4.
http://hsgac.senate.gov/public/_files/052008Masters.pdf
Bottom of Page 4.