A single dataset would not be stored in 6 separate worksheets. That would be 6 separate datasets. If the data is related you might be able to combine them.
How did you convert the workbook into SAS datasets? Did the worksheet with the 1,069 rows yield a dataset with 1,068 observations (assuming the first row in the worksheet has column headers that SAS can use to guess what names you want to use to refer to the variables it creates).
The usual reason why only 30 out of 1,068 observations participate in an analysis is that observations with missing values for one or more of the variables are excluded. How many variables are in the dataset you used for the analysis? How many of the variables did you use in the analysis? How many missing values do the variables have?
