Ratios (photon units) of SOHO/NIS EUV irradiances in lines from He and other ions which should be approximately constant with the solar cycle. The dashed lines correspond to the values from the averaged Skylab ATM radiances in the quiet Sun, while the diamond refer to the SDO/EVE prototype spectrum of 2008 April 14. The full line indicates the irradiance ratios from the Heroux et al. (1974) measurements.