AVG_LEAF_BLOCKS_PER_KEY and AVG_DATA_BLOCKS_PER_KEY - value is always 1?

iWhat hi,

Can these two columns be any other than value besides 1 ?

AVG_LEAF_BLOCKS_PER_KEY and AVG_DATA_BLOCKS_PER_KEY.

I couldn't find anything in documentation on these two columns and found them curious

thanks

SQL> SELECT BLEVEL, LEAF_BLOCKS AS "LEAFBLK", DISTINCT_KEYS AS "DIST_KEY",
AVG_LEAF_BLOCKS_PER_KEY AS "LEAFBLK_PER_KEY",
AVG_DATA_BLOCKS_PER_KEY AS "DATABLK_PER_KEY"
FROM DBA_IND_STATISTICS
WHERE OWNER = 'SOE' AND INDEX_NAME = 'EMP2_EMPNO_UQ';

  BLEVEL  LEAFBLK  DIST_KEY LEAFBLK_PER_KEY DATABLK_PER_KEY
---------- ---------- ---------- --------------- ---------------
     1     2    879        1        1

SQL>