sysstatistics table

The sysstatistics table stores one or more rows for each indexed column on a user table; it also stores statistics for unindexed columns:

For more information on prefix subsets, see “Column statistics”.

Additional rows store histogram data for the leading column. Histograms do not exist if indexes were created before any data was inserted into a table. To generate a histogram, run update statistics after inserting data.

See “Histogram displays”.