By Mark Mallabone and Geraldine Capp CANBERRA AUSTRALIANS are among the world's biggest cannabis users. However, an Australian Institute of Health and Welfare report to be released today found that the traditional vices of smoking and drinking had lost some of their appeal. Australia had slipped down the international ladder in tobacco use since 1990 and alcohol consumption also was on the wane. Statistics on Drug Use In Australia 2000 found that cannabis was more widely consumed in Australia than in countries with liberal drugs laws such as The Netherlands. The proportion of Australians aged 14 and older who had used it in the past year (18 per cent) exceeded Britain or the United States (9 per cent), Spain (8 per cent), Canada (7 per cent) and The Netherlands (5 per cent). In comparison, Australia has fallen to 17th in world cigarette smoking per head of population after beginning the 1990s ranked 8th. Health Minister Michael Wooldridge will unveil figures today showing smoking rates among Australian adults dipped to 20.3 per cent late last year from 23.7 per cent in 1997. And it was placed 19th in average alcohol consumption (7.6 litres). Luxembourg was top with 13.3 litres, then Portugal with 11.2 and France with 10.8. Australian drinking levels fell slightly in the past decade, having reached 7.8 litres per head of population in 1993-94. The health and welfare report shows the proportion of Australians aged 14 and older who have used cannabis increased to 39.1 per cent in 1998 from 32.5 per cent in 1991. Similar increases were recorded for use of heroin (2.2 per cent from 1.7 per cent), amphetamines (8.8 per cent from 7.6 per cent) and designer drugs such as ecstasy (4.8 per cent from 2.2 per cent). Illicit drug use, including cannabis, during the past year was more prevalent in WA than any other State. Nevertheless, the number of cannabis offences recorded in WA per 100,000 of population has declined from 780 in 1995-96 to 329 in 1998-99. Curtin University national drug research institute fellow Simon Lenton said the report's international comparisons must be interpreted cautiously because countries used different methods, creating the possibility of survey bias. The full picture of Australian illicit drug use required an international com parison of the consumption of all types of illicit drugs - not just cannabis. But Mr Lenton noted that Australia's cannabis use appeared greater than that of countries with much more liberal drug laws. Australian workers were not afraid to dob in co-workers they knew used illicit drugs at work, recruiting company TMP Worldwide spokesman Leigh Anderson said yesterday. More than 79 per cent of men and 69 per cent of women in a survey of 6000 employees said they would dob in a colleague they saw taking drugs in the office. Nearly 88 per cent of organisations for which they worked saw drug use at work as a sackable offence. However, 43 per cent believed their employer should offer drug education and rehabilitation programs for offenders. Not all employers believed they had that responsibility.