Chapter 4 is written by Jan T. Klovland. Klovland presents data for bond yields from 1820 to 2003. The first part concentrates on sources and methods for measuring monthly yield data on bonds issued by the Norwegian government (from 1820 onwards), Kongeriket Norges Hypotekbank, as well as on private bonds in the period after 1921. The bond yield estimates are derived from market quotations for Norwegian bonds traded on the main financial bourses of Northern Europe. Before 1921 the character of the bonds only permits the computation of the average yield on long-term maturities. After 1921, however, the data encompass all maturities along the yield curve, with some gap at the short end in the early years.