The answers to the following clues will have something in common.

1. Ideal employee
2. Baseball perfection
3. Exceptional
4. Sawbucks
5. Grand
6. C-Notes
7. Catchphrase associated with Carl Sagan
8. Lightyear distance measure
9. St. Lawrence River archipelago
10. It's for the money
11. Tithe amount
12. Penny

Answers:

All the number words can be expressed as powers of 10.

1. Hundred percenter
2. Batting a thousand
3. One in a million
4. Ten-dollar bills
5.  A thousand dollars
6. Hundred-dollar bills
7. Billion and billions
8. Trillion miles
9. Thousand Islands
10. One
11. One-tenth
12. One-hundredth of a dollar

Credit: NY Times Crossword - Nov. 30, 1986
Harold B. Counts  [no pun intended]
DECIMAL DESCRIPTIONS