美国2009年的研究表明美国人的平均寿命有望超出78岁

http://www.lbnelert.com/wp-content/uploads/2011/03/Life-Expectancy.jpgU.S. LIFE EXPECTANCY  PASSES 78: Maybe this good news will keep them from crying: Babies born in 2009 have a life expectancy of 78 years, two months, according to the Center for Disease  Control—an all-time high. The new figure is based on a drop in the number of deaths, which fell by 36,000 to 2.4 million deaths in 2009. One cause for concern: Despite the overall life expectancy increase, it held steady for black Americans.