Taiwan launched a single-payer National Health Insurance program on March 1, 1995. As of 2007, 22.60 million of Taiwan’s 22.96 million population were enrolled in this program. Foreigners in Taiwan are also eligible for this program. The database of this program contains registration files and original claim data for reimbursement. Large computerized databases derived from this system by the Bureau of National Health Insurance, Taiwan (BNHI) and maintained by the National Health Research Institutes, Taiwan, are provided to scientists in Taiwan for research purposes.