dbcc show_statistics output

statistics for INDEX 'OrderID'.
Updated              Rows  Rows Sampled Steps  Density        Average key length       
-------------------- ----- ------------ ------ -------------- ------------------
Oct  2 1999  6:44PM  2155  2155         270    1.1922787E-3   7.9999347
(1 row(s) affected)

1. Updated is the date and time the statistics were last updated.
2. Rows is the number of rows in the table.
3. Rows Sampled is the number of rows used to generate the statistics information.
4. Steps is the number of distribution steps.
5. Density is the selectivity of the index.
6. Average key length is the average length of a row.

All density              Columns                                                                                                                          
------------------------ ---------------------------------------- 
1.2048193E-3             OrderID
4.6403712E-4             OrderID, ProductID
(2 row(s) affected)

1. All density is the selectivity of the specified order column list in the index.
2. Columns is the list of the index columns for which all the density is displayed.

Steps       

----------- 
10248      
10251      
10253      
10256      
10259      
10262      
10264      
10857      
10860      
10863      
10866      
10869      
10872      
10954      
(270 row(s) affected)

1. Steps is the values in the current distribution statistics for the specified index or statistics group on the specified table.