In 1971 the United Kingdom changed its currency to the decimal system. In 1972, Dr. Francine Patterson started to teach sign language to Koko. In 1978 a peace treaty was concluded between Japan and China. In 1979, Mother Teresa won the Nobel Peace Prize. in 1980s In 1987, the first single-use disposable cameras were offered for sale. in 1994 In 1994, there was a shortage of water and rice in Japan. In 1994, there were 3.7 million cohabiting couples in the United States. In 1995, Andou received architecture's most prestigious award. In 1995, sales of hardbacks dropped by 3.1 percent. In 1997, he filed for personal bankruptcy.