While costing index access, dbcc traceon(302) prints a set of statistics for each useful index. This index block shows statistics for an index on au_lname in the authors table:
Estimating selectivity of index ’au_names_ix’, indid 2 scan selectivity 0.000936, filter selectivity 0.000936 5 rows, 3 pages, index height 2, Data Row Cluster Ratio 0.990535, Index Page Cluster Ratio 0.538462, Data Page Cluster Ratio 0.933579
