I got 100%, but it took me a second to figure out the fancy-pants AMERICA columns. I thought each word had to start with the letter above that column. Apparently not. :)
I've had to sing this so many times but funnily enough, have never known the lyrics, just the general sounds of the words and the tune. I tried all different combinations of "ample fields of green" and "amble seas of gray" for "amber waves of grain". I also thought "crown" was "bound".
I pulled out 100%. I probably haven't sung this since grade school. I'm glad to know the words are still up there somewhere in my brain amongst all of the classic rock and 90s song lyrics.
I feel kind of stupid.
For smoggy skies
Insecticided grains
For strip-mined mountains, majesty
Above the asphalt plains.
America, America,
Man sheds his waste on thee
And hides the pines
With billboard signs
From sea to oily sea!
RIP Carlin
However, I do feel obliged to point out that there are more verses to the song. I could never get the lyrics to those but they do exist:
http://www.scoutsongs.com/lyrics/americathebeautiful.html