The chuckwagon drivers auction advertising space on their wagons before each year's Stampede. The first advertisement on the tarp cover of a chuckwagon was made in 1941, and Lloyd Nelson was the last person to win the Rangeland Derby without a sponsored wagon, doing so in 1956. The current practice of selling advertising via a tarp auction began in 1979. The revenue generated by the auctions, a record $4 million for the 2012 Stampede, is considered an indicator of the strength of Calgary's economy.