THE number of mainland visitors to Hong Kong has been growing fast, especially in the last two years. No fewer than 1.73 million visitors crossed the border last year and 1.57 million of them were Chinese nationals. What is most striking about this new force in the tourist trade is how little it differs from other countries' visitors. However, the differences that do exist tend to be substantial - and this is perhaps the most important factor for tourist chiefs in Hong Kong to bear in mind. The Hong Kong Tourist Association (HKTA), after its recent annual meeting, made much of the mainlanders' estimated level of spending per head. Yet there is probably greater guesswork in the figure than for other arrivals. For example, people from other countries tend to spend more on accommodation than mainlanders. Against that, mainlanders tend to stay significantly longer in the territory than the average visitor from elsewhere. So what is the profile of the mainland visitor? According to the HKTA's research in 1993, the percentage of male visitors from China is slightly higher than from other countries - 65 per cent compared to 62 per cent - but it is about the same as the proportion from Taiwan. The average age of mainland visitors is about the same as that for all countries at 39.6 compared to 39.1, although fewer mainland children and teenagers tend to visit to Hong Kong. Like visitors from other areas of the world, most mainland arrivals - 74 per cent - say they would like to return. The overall figure is 78 per cent. But this is where the mainland visitor profile tends to part quite markedly from that of the average visitor from elsewhere. Senior white collar workers make up a much lower percentage of the mainland visitors - 43 per cent compared with 57 per cent for all countries - but this probably partially reflects the make-up of mainland society. Fewer of the mainlanders who arrive in the territory are on holiday - 34 per cent compared with 54 per cent - while many more are in Hong Kong on business - 36 per cent compared with 31 per cent. Many more are also, not surprisingly, visiting friends and relatives - 12 per cent versus five per cent - and a large proportion are en route to somewhere else - 17 per cent compared with nine per cent. More importantly for the hotel industry, mainland visitors often have somewhere to stay other than commercial accommodation. Only 65 per cent stay in hotels and guest houses compared with 84 per cent of the arrivals from all countries. But mainland visitors stay longer in the territory - 5.7 nights compared with the average of 3.8 nights for all visitors. Most surprisingly, more than 53 per cent of the mainland visitors to the territory in 1993 had never been to the territory before, while this applied to only 46 per cent of those from the rest of the world. By far the majority of mainland visitors, like visitors from elsewhere, have arrived in Hong Kong on a travel deal other than a package tour (65 per cent compared with 54 per cent overall). The same comparisons remain true for mainland visitors who are purely tourists, as opposed to business visitors in transit. But mainland visitors seem to have little interest in sightseeing (25 per cent compared with 56 for all visitors). About 10 per cent of visitors from the mainland are people who live in China but are not Chinese nationals. Ian Perkin is chief economist with the Hong Kong General Chamber of Commerce. The views expressed in this column are his own and may not necessarily reflect chamber policy.