They say friends are forever, but as it turns out, that old adage is actually not quite true.

人们都说“友谊地久天长”，科学家却证明，这条老格言未必十分可信。

More than two thirds of Americans say they have lost at least 90 per cent of the friends they had 10 years ago.

However, according to a new survey of 1,000 people across the country, BFFs may be more true to their name as 55 per cent of people say they have kept the same best friend over the last decade.

The poll also shows that you lose more friends when entering into a romantic relationship than when leaving one.

In fact, entering a relationship is the third biggest cause of losing friends – the top two being moving away to a new city and simply drifting apart. Thirty per cent of respondents admit they have lost friends in a break-up.

Americans estimate that they have an average of four close friends. Sadly, eight per cent say that they have no close friends at all.

But, surprisingly, people age 55 and up are nearly twice as likely to have over 15 close friends than those between the ages of 18 and 24.