Early last year around 60 per cent of taxi drivers surveyed by the National Transport Authority said they worked between 8 and midnight
But that dropped to under half in the later half of the year.
The fall off was then more pronounced after midnight with only 38 per cent of drivers working.
Personal safety was the main reason given, followed by health reason - while 1 in 10 said it just wasn't worth their while financially.
When asked what would persuade them to work at night - a third said 'nothing would'
The survey gives weight to public complaints about how tough it can be to get a taxi home at the end of a night out.