The average total cost of a family health insurance plan reached $15,745 this year, an increase of 4 percent since 2011, report the Henry J. Kaiser Family Foundation of Menlo Park, Calif. and the Chicago-based Health Research and Educational Trust. Workers paid an average of $4,316 for those plans with their employers paying the rest, according to the survey, which was conducted between January and May. In 2002, job-based family coverage cost $8,003.