How can I rank a group of values?

Column F has some values calculated every 6th row. I would like to, in another column, put the "ranking" of each of those values.

For instance:
F1 - 900
F7 - 500
F13 - 200
F19 - 1000
F25 - 600

G1 would read "2"
G7 would read "4"
G13 would read "5"
G19 would read "1"
G25 would read "3"

Is this possible? is there a formula that can do this?