The extreme observations output by default or with the NEXTROBS= option on the PROC UNIVARIATE statement are automatically labeled with the observation number. Beginning with SAS9, when BY processing is used, the labels are the observation numbers from the whole data set. Prior to SAS9, when BY processing is used, the labels are the observation numbers from within the current BY group. With the previous method, the observation numbers start at 1 within each BY group. With the current method, the numbering is continuous throughout the data set.