In the United States, for example, the top 1% of the population received 18% of pre-tax income in 2008, up from 8% in 1980. While the income share of the top income recipients also rose in most other OECD countries (Figure 8), there is great variation across countries with respect to both the extent of this increase and the time when it started. Despite a growing interest in the rise in top incomes, there is still substantial disagreement about the causes and their relative importance. Studies estimating the elasticity of taxable income at the top with respect to the marginal tax rate typically put it at around minus one for a top marginal tax rate of 50%.