Why is the name Jehovah not used more in the Book of Mormon?

In Jewish history around 150 years before Christ came Jews began taking the name Jehovah out of the Bible. In the book of Mormon, the record of the bible is on brass plates claimed from Laban 600 BC. Why is it that in the 600 BC version the name Jehovah only appears once when quoting the Bible, when in the old testament manuscripts it appears over 7,000 times? My question is relating mainly to when books of the old testament are quoted in the Book of Mormon. Mostly in 2 Nephi.