Year ended December 31 | ||||||||||||
2013 | 2012 | 2011 | ||||||||||
U.S. statutory federal income tax rate | 35.0 | % | 35.0 | % | 35.0 | % | ||||||
Effect of income taxes from international operations at rates different from the U.S. statutory rate | 5.1 | 7.8 | 7.5 | |||||||||
State and local taxes on income, net of U.S. federal income tax benefit | 0.6 | 0.6 | 0.9 | |||||||||
Prior-year tax adjustments | (0.8 | ) | (0.2 | ) | (0.1 | ) | ||||||
Tax credits | (0.5 | ) | (0.4 | ) | (0.4 | ) | ||||||
Effects of changes in tax rates | — | 0.3 | 0.5 | |||||||||
Other | 0.5 | 0.1 | (0.1 | ) | ||||||||
Effective tax rate | 39.9 | % | 43.2 | % | 43.3 | % | ||||||