A comparison of the healthcare systems in Canada and the United States is often made by government, public health and public policy analysts. The two countries had similar healthcare systems before Canada changed its system in the 1960s and 1970s. The United States spends much more money on healthcare than Canada, on both a per-capita basis and as a percentage of GDP. In 2006, per-capita spending for health care in Canada was US$3,678; in the U.S., US$6,714. The U.S. spent 15.3% of GDP on healthcare in that year; Canada spent 10.0%. In 2006, 70% of healthcare spending in Canada was financed by government, versus 46% in the United States. Total government spending per capita in the U.S. on healthcare was 23% higher than Canadian government spending. And U.S. government expenditure on healthcare was just under 83% of total Canadian spending (public and private). Studies have come to different conclusions about the result of this disparity in spending. A 2007 review of all studies comparing health outcomes in Canada and the US in a Canadian peer-reviewed medical journal found that "health outcomes may be superior in patients cared for in Canada versus the United States, but differences are not consistent." Some of the noted differences were a higher life expectancy in Canada, as well as a lower infant mortality rate than the United States. One commonly cited comparison, the 2000 World Health Organization's ratings of "overall health service performance", which used a "composite measure of achievement in the level of health, the distribution of health, the level of responsiveness and fairness of financial contribution", ranked Canada 30th and the US 37th among 191 member nations. This study rated the US "responsiveness", or quality of service for individuals receiving treatment, as 1st, compared with 7th for Canada. However, the average life expectancy for Canadians was 80.34 years compared with 78.6 years for residents of the US. The WHO's study methods were criticized by some analyses. While life-expectancy and infant mortality are commonly used in comparing nationwide health care, they are in fact affected by many factors other than the quality of a nation's health care system, including individual behavior and population makeup. A 2007 report by the Congressional Research Service carefully summarizes some recent data and noted the "difficult research issues" facing international comparisons. Government involvement In 2004, government funding of healthcare in Canada was equivalent to $1,893 per person. In the