The picture above exemplifies a pivot table and one of the many different ways it can be utilized. One of the main reasons pivot tables can be such amazing tools for representing data is how interactive they can be. The table above shows sales by each country sorted chronologically by week. The table is very easily changed to reinterpret the data to be sorted by country instead of by time. Pivot tables allow the user to represent their total sales by region, or even be specific salespersons. They also can allow the ser to group data into even more specific groups such as other time periods (months, years, etc), or other custom grouping methods. This is shown in the pivot table below.

In terms of efficiency, there is no better table to use than a pivot table. They can save you hours by allowing the user to quickly change how a data set is represented. They also add a sense of flexibility. Pivot tables make it very easy to incorporate any new data that may be found instead of having to create a whole new table/chart.