Seventy-four-year-olds are the most contented people in the population, according to new research.
Fewer responsibilities, financial worries and more time to yourself leads to contentment（满意，满足） previously unknown in earlier life.
According to the report from the teenage years until 40 happiness declines. It levels off until 46 and then starts to increase until peaking at 74.
Scientists from Germany and America regularly questioned 21,000 men and women how happy they were with their lives providing a scale from one to seven - seven indicated complete contentment.
Teenagers in their late teens marked themselves at around 5.5 which fell to around 5 by age 40.
At 74 happiness averaged at 5.9.
The report, published in the journal Social Indicators Research, said this could be due to older people being more appreciative（感激的，有欣赏力的） .
It concluded: "Compared to younger individuals, older people tend to place a greater emphasis on（强调，着重于） emotional aspects of social interactions and are likely to remember the emotional content of their experiences."
Bringing up a family, buying a house and creating a career added to the stresses experienced by those in their twenties and thirties.
The change in happiness was apparently most pronounced amongst British respondents（回答者，调查对象） . German men and women reported relatively stable levels of satisfaction throughout their lives.
Dr Carlo Strenger, from Tel Aviv University, said: "If you make fruitful（多产的） use of what you have discovered about yourself in the first half of your life, the second half can be the most fulfilling.
"Most people can anticipate a second life, if not a second career."