求翻译：美国IBM公司从1984年左右开始由兴转衰，由年盈利66亿美元到1992年亏损达49.7亿美元。衰落的一个主要原因是失效的董事会监督。是什么意思？

IBM, the United States around 1984 by the Xing and doom, the annual profit of $ 6.6 billion loss in 1992 reached $ 4.97 billion. A major reason is the decline of the failure of board oversight.

The United States company IBM from around 1984 by Hing to recession, from $6.6 billion in annual profits to the 1992 losses amount to $4.97 billion. A major cause of the decline is ineffective oversight board.

American IBM Corporation started from 1984 by to be popular the extension to fade, gained to lose money 6,600,000,000 US dollars from the year to 1992 amounts to 4,970,000,000 US dollars.A decline primary cause is the expiration board of directors surveillance.

United States IBM company began to decline from around 1984, from annual profit of $ 6.6 billion by 1992 losses of $ 4.97 billion. A major cause of the decline is the failure of the Board of supervision.

IBM, the United States around 1984 by the Xing and doom, the annual profit of $ 6.6 billion loss in 1992 reached $ 4.97 billion. A major reason is the decline of the failure of board oversight.