Rosetta is the first spacecraft where the gaseous envelope of the spacecraft arising from outgassing has been measured with very high sensitivity, down to partial pressures of ~10-15 mbar. Measurements cover more than six years and a large range of heliocentric distances (0.8 - 4 AU). Here, we report outgassing studies of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) for the last six years.