Histogram of the ratio between daily F_10.7 data and the mean F_10.7 value (after subtraction of a 67 sfu base quiet-Sun flux), for all data with S_N > 15. The black curve is for the entire data series, while the blue and red histograms are respectively for the maxima of the solar cycles (time of maximum −2 to +3 years) and the minima (the rest of the data). The distributions are slightly asymmetrical with a longer upper wing. The means of the distributions are indicated by thick vertical lines, with the matching colors. The standard deviation of the distributions equals 35%, while the SEM equals 0.5% (based on more than 10,000 daily ratios in each distribution). The distributions for cycle maxima and minima are significantly shifted by 12% above and below the global mean.