X11 output C 19 - Original Series Adjusted for Trading-day and Prior Variation

The values in C 18 are used to adjust the original (adjusted) series (in A 3 or B 1 ). Specifically, the values in C 18 are subtracted from (additive model) or divided into (multiplicative model) the original series.
For more information, see X-11 Census Method II Seasonal Adjustment .