Upper panel: Ratio of the normalized EIT 304 Å light curve to the CELIAS/SEM first-order light curve. The linear functions fit to each inter-bakeout period are plotted in pink. The vertical red line marks November 12, 2008, the (rough) time after which the inter-bakeout trends start to get noticeably worse. Note: SEM time series ends on February 8, 2024 (earlier than our EIT light curves), so this ratio plot also ends on February 8, 2024. Lower panel: Residuals of the linear fits.