select   substr(table_name,1,20)       partitioned_table,
         substr(column_name,1,20)      key_column,
         count(*)                      no_stats,
         count(*)/total_partitions*100 "NO_STAT%"
from     (
         select table_name,
                column_name,
                partition_name,
                low_value,
                count(*) over (partition by table_name, column_name)
                   total_partitions
         from   user_part_col_statistics
         where  (table_name,column_name) in
                (select name,column_name
                 from   user_part_key_columns
                 where  object_type = 'TABLE')
         )
where    low_value is null
group by table_name,
         column_name,
         total_partitions
/