Developing countries face an even more critical disparity in primary care practitioners. The Pan American Health Organization reported in 2005 that "...the Americas region has made important progress in health, but significant challenges and disparities remain. Among the most important is the need to extend quality health care to all sectors of the population...Experience over the last 27 years shows that health systems that adhere to the principles of primary health care produce greater efficiency and better health outcomes in terms of both individual and public health..." [22] The World Health Organization (WHO) has identified worsening trends in access to PCPs and other primary care workers, both in the developed and the developing nations:[23]