This study is based on (1) historic population and energy data from 1965 to 2008 and (2) backup studies by several scientists. The Olduvai Theory is explained by disaggregating the World into the U.S., the Organisation for Economic Co-Operation and Development (OECD) nations, and the non-OECD nations standards of living (SL). The U.S. SL peaked in 1973 (Figure 1). The World SL rapidly increased from 2000 to 2007 (Figure 2). This increase was caused by just a few nonOECD nations (Figure 3). The OECD SL peaked in 2005 (Figure 4). The Olduvai Theory shows each SL curve trending toward the same average SL value that the World had in 1930 (Figure 5).