A variety of cross-section data for electron-impact ionization of N2 have been analyzed, including those for total N+2 production and for the Meinel and first-negative emissions from excited N+2 ions. These results are used to infer the relative production rates of the N+2(X), N+2 (A), and N+2(B) product ions during the reactions, yielding branching-ratio fractions of 0.320¿0.147, 0.535¿0.112, and 0.145¿0.019, respectively, for 100-eV electrons. The data are compared with the relative formation rates of these ions recently obtained using electron-energy spectroscopy coincidence measurements. The significant discrepancy between these two procedures is discussed, and the results obtained from our data analysis are recommended for auroral modeling at the present time. ¿ American Geophysical Union 1995