Yesterday, I noticed a news item about Jackson Browne being a 2007 inductee into the Songwriter's Hall Of Fame (SHOF). Lightfoot and Leonard Cohen were among the nominees, and may have been nominated many times in the past. I couldn't find that particular info. I'm aware that Lightfoot has been inducted into the Canadian SHOF.
Anyhow, here is a link to the SHOF website. Interesting perusing for those so inclined :
SHOF