this post. Third paragraph.
Credible? You decide.
Replaced by this one on the MGP (new owners) site.
The percentage of rye is indicated for the Rye Whiskey, but for the three bourbons it would appear that the figure given is for the percentage that is not corn, which suggests that whoever authored the page is not what you'd call bourbon knowledgeable.
Fortunately the listed whiskeys link to pages which give the actual mash bill.
Some interesting looking stuff down under Alcohol - Food Grade Industrial. The SDA-29 sounds tasty...(Homer Simpson voice)...mmmm....acetaldehyde....