The top departments simply performed better this year than the same time period last year.
The sales numbers we focus on for departments are the comps, or comparisons to previous years sales. If you are comping up is means that compared to last year you have sold more dollars worth of product. Last week, for example, luggage was 20% off on cartwheel and sold really well. Compared to last year, we were up 40% which was our highest comp. Some departments sold worse than last year, so they comped down.
You can look all the way from total store sales(what really matters) to departments to specific categories. Sometimes products move around and categories are added or removed, and that can affect reporting at the more granular levels. It's important to not focus on the categories too much as there can be huge variances and the sales are small. It's not a good idea to stress about being down 5% in a department that did $500 in sales, but the reporting is there if needed.
