Pulitzer Prize for Poetry

The Pulitzer Prize for Poetry is one of the seven American Pulitzer Prizes given every year for "Books, Drama, and Music". It was first given in 1922.
The prize is given "For a distinguished volume of original verse by an American author." That means it is given for an important book of original poetry. The book must be published during the calendar year before the prize is given.
Since 1980, two finalists (other important books) have been named at the same time as the winner.
1918 and 1919 special prizes.
Before the establishment of the award, the 1918 and 1919 Pulitzer cycles included three Pulitzer Prize Special Citations and Awards (called at the time the Columbia University Poetry Prize) for poetry books funded by "a special grant from The Poetry Society."
Winners.
In its first 92 years to 2013, the Pulitzer Prize for Poetry was awarded 92 times. Two were given in 2008, none in 1946. Robert Frost won the prize four times and some other poets won it more than once).
1980s.
Indented entries are finalists after each year's winner.
1990s.
Indented entries are finalists after each year's winner.
2000s.
Indented entries are finalists after each year's winner. Two prizes were awarded in 2008.
2010s.
Indented entries are finalists after each year's winner. 
2020s.
Indented entries are finalists after each year's winner.