"Global average sea level has risen since 1961 at an average rate of 1.8 (1.3 to 2.3) mm/yr and since 1993 at 3.1 (2.4 to 3.8) mm/yr".
Climate Change 2007 Synthesis Report Intergovernmental Panel on Climate Change
Sea-level trends from satellite altimetry, 1992-2008. Space data provides the most accurate and best calibrated long-term observations of changes in sea-level height, to improve stability, accuracy, precision and consistency of records.