Complex sentence: Lionel's efforts to diversify failed to compensate for the public's declining interest in its toy trains, by 1966, Lionel's revenue was $28 million dollars, 40 percent from government contracts.
Split into simpler sentences: Lionel's efforts to diversify were unable to make up for the public's declining interest in its trains. By 1966, Lionel's total revenue was $28 million, 40 percent of which came from government contracts.