Rare walking liberty halves

The rare dates for walking liberty halves and their associated mintages are as follows:

1916 608,000

1916D 1,014,000

1916S 508,000

1921 246,000

1921D 208,000

1921S 548,000

1938D 491,600

Additionally, it should be mentioned that even common dates can be extremely rare in choice uncirculated condition.