The marriage rate in the United States has plummeted to its lowest level in over a century, a new study has found.Fewer women in the US are getting married and they are waiting longer to do so, according to a new family profile from the National Center for Family and Marriage Research (NCFMR) at Bowling Green State University. The current marriage rate is 31 to 1, the lowest it has been in over a century. That ratio equals roughly 31 marriages per 1,000 married women. In 1920 the marriage rate was 92 to 3. The average age at first marriage for women is the highest it has been in over a century, at nearly 27 years old, according to the study. The researchers warned that since 1970, the marriage rate in the US has declined by almost 60 percent. "Marriage is no longer compulsory. It's just one of an array of options. Increasingly, many couples choose to cohabit and still others prefer to remain single," said Dr Susan Brown, co-director of the study. "The age at first marriage for women and men is at a historic highpoint and has been increasing at a steady pace," said Dr Wendy Manning, co-director of the Center. The proportion of women who have been divorced or separated has also increased to 15 percent as opposed to 1920 when it was only 1 percent. "The divorce rate remains high in the US, and individuals today are less likely to remarry than they were in the past," said Brown. Researchers said the marriage rate has declined for all racial and ethnic groups, but the greatest decline is among African Americans.