Fig. 4From: Population monitoring of trisomy 21: problems and approachesRaw (circle) and age adjusted (dot) monthly birth prevalence of Down syndrome from January 1981 to December 1992 in Belarus (N = 1,720,030; n = 1791) and West Berlin (N = 218,497; n = 237) based on a change point model allowing a decreasing trend with a peak in January 1987 and a jump, i.e. a level shift, for 1987 to 1992. Belarus: ORpeak p < 0.0001, ORjump p = 0.0001; West Berlin: Orpeak p < 0.0001, ORjumpp = 0.378 [from 64]Back to article page