I'm researching the origins of a folk song from Botswana called "Ke Mo Boitumelong" or "I am Happy". The English lyrics are:

I am happy. (x2)
Because of Jesus Christ.
I am happy.
He has taken them all -
Taken all my sins.
Now I am happy.

Here's a link to the song on iTunes:

http://phobos.apple.com/WebObjects/MZStore.woa/wa/viewAlbum?i=215128202&id=215128183&s=143441

All of the information I have about the song is from a Folkways Records album called Traditional Music of Botswana, Africa recorded and Annotated by Elizabeth Nelbach Wood. It's from 1983. She indicates that it is a hymn set to a traditional tune.

Does anybody know anything else about this song? How old is it? Is it a missionary creation? Does it date back to the time when Botwana was Bechuanaland? Has it ever been published anywhere else?

I'd appreciate any insights you all have...