Pioneer Venus Orbiter ultraviolet spectrometer data from 20 orbits which span 3 years have been analyzed to determine the atomic hydrogen number density and vertical flux at the exobase as a function of solar zenith angle, F10.7 index, and spacecraft latitude. From 1979 through 1981 the exobase number density nc and flux ϕc are remarkably constant at nc=6.0¿1.5¿104 cm-3 and ϕc=7.5¿1.5¿107 cm-2 s-1 in the subsolar region. The integrated vertical column density above 110 km is 3.6¿1¿1013 cm-2. An empirical relationship is determined between the line center solar flux at H Lyman &agr;, &pgr;F0, and the F10.7 index. At 1 AU, &pgr;F0=(2.0+1.1¿10-2F10.7)¿1011 photons cm-2 s-1 ¿-1. ¿ American Geophysical Union 1988