The Kaiser Family Foundation released a new primer that explains recent trends in healthcare costs in the United States and the factors that contribute to their growth. Prepared by Foundation staff, the primer examines the rapid growth in the nation's healthcare costs since 1970, when the average growth in health spending exceeded the growth of the economy as a whole by an average of 2.5 percentage points. The share of the economy devoted to healthcare grew from 7.2% in 1970 to 16% in 2005 and is projected to increase to 19.6% by 2016. Between 2000 and 2006, insurance premiums for family coverage rose 87%, more than four times the growth in wages. The primer describes the types and sources of healthcare spending, the demographic factors associated with higher or lower levels of spending, and the impact of higher premiums and out-of-pocket costs on families. It also discusses other factors that influence healthcare spending growth, including the use of new medical technology, population changes, and changes in disease prevalence. "Health Care Costs: A Primer" is available online at http://www.kff.org/insurance/7670.cfm.