This file contains a data table representing the average power spectrum, P_n, of Nambu-Goto cosmic strings evolved under numerical gravitational backreaction. The power spectra and the methods used to produce them are reported on in "Numerical gravitational backreaction on cosmic string loops from simulation" [to appear], by the same authors as this dataset. See Fig. 5 of that paper for a visualization. The file is organized in three columns: The fraction of evaporation, chi. The range is from 0.0 to 0.7 in steps of 0.1. The mode number, n. The range is from 2^0 to 2^39 in multiplicative steps of 2. The logarithmically binned elements of the power spectrum, nP_n. Bin edges are 2^i to 2^(i+1)-1 for i from 0 to 39.