By means of a plane grating spectrometer aboard the German-U.S. satellite Aeros A, solar EUV fluxes have been measured in the wavelength range from 16 to 106 nm monitoring the emission from the full solar disk from December 1972 through August 1973. The instrument was calibrated before flight by means of the radiation produced by an electrons synchrotron. The sensitivity of the multipliers was continously monitored in flight. EUV indices are presented characterizing the most important solar emissions of aeronomic interest orbit by orbit. The data clearly show a long-term decrease with smoothed sunspot numbers superposed by a kind of solar rotation modulation, both effects being more important for higher ionized emissions. By comparing both variations with those of the classical solar activity indices it is found that the 27-day period appears more consistently in the Covington index than in EUV emissions. The Zurich relative sunspot number, however, shows much larger fluctuations. Both traditional indices are therefore not ideal for characterizing solar-terrestrial relations, in particular in aeronomy.