World and U.S. energy intensities have declined over the past century, falling at an average rate of approximately 1.2–1.5 percent a year. The decline has persisted through periods of stagnating or even falling energy prices, suggesting the decline is driven in large part by autonomous...

Australian employers are obliged by law to make a minimum compulsory contribution as a proportion of salaries into employees' superannuation (pension) funds. Individuals can also make voluntary contributions on top of the compulsory amount. We examine voluntary contributions amongst two groups...