1. BLS (2012), Table 1. 2. OMB (2012).
2. Thornton (1984).
3. “Just More of the Same,” The Economist, February 11, 2012, at
http://www.economist.com
/node/21547248/print (accessed February 20, 2012).
4. Taylor (2012).
5. Hummel (2011a), p. 512. 7. Original data obtained from private correspondence with John Frain,