Upper panel: Ratio of the normalized EIT 304 Å light curve to the CELIAS/SEM first-order light curve. The two exponential functions fit to the post-2012 dropoff are plotted in blue and red, respectively, with best-fit parameters given in the figure legend. t₁, the beginning of the first exponential trend, is January 11, 2012, and t₂, the beginning of the second exponential trend, is June 3, 2016. Note that the SEM time series ends on February 8, 2024 (earlier than our EIT light curves), so this ratio plot also ends on 8 February 2024. Lower panel: Residuals of the exponential fit.