SUCH a rosy picture of the world economy is painted by the Organisation of Economic Co-operation and Development (OECD) that it is hard to appreciate why the performance of the world stock markets should be so lacklustre this year. Or could it be that the momentum now being enjoyed is taking the global economy towards its next, inflationary, crisis? All the major centres of economic power - the United States, Europe, Japan, Southeast Asia and China - are given a good mid-year report by the Paris-based group. Perhaps the most heartening aspect of the OECD six-monthly assessment is the uniformity of the performances. No huge winners, but then no big losers among the key economies either. The US is the biggest concern, with growth expected to slow to three per cent in 1995 from four per cent this year, but that is hardly a reason for tears. More worrying is the forecast jump in interest rates to 4.75 per cent this year, and on to 5.25 per cent next year. That's certainly one reason for stock market doldrums. But against this are the improving fundamentals elsewhere. Germany, the engine of Europe, is bound for 1.8 per cent growth this year, and 2.6 per cent next. Not breakneck, so certainly not dangerous. The recent dying away of the lower interest rate trends might even be resumed in Germany as inflation comes down, says the OECD. Even Britain, the former basket case, is now on its way to growth of 2.8 per cent this year and a healthy 3.2 per cent next. Again, without an inflation penalty, according to the OECD. The question mark still remains over Japan. The rising yen is the unknown factor, and could slow down recovery prospects. But even so the OECD forecasts 2.7 per cent growth for 1995. That's still convalescent rather than sprightly, but this is an economy which has to face up to some maturity. The top scorers on the OECD card remain the Southeast Asian dragons, or, as the latest acronym has it, the DAEs, Dynamic Asian Nations. If the cap fits . . . And South Korea, Hong Kong, Malaysia, Singapore, Taiwan and Thailand are all entitled to wear it, says the OECD. Their average gross domestic product growth this year is expected to be 6.9 per cent, against 6.4 per cent in 1993. Next year should see the same again. This is a truly remarkable performance for nations which have come a long way since they were LDCs (less developed countries) or NIEs (newly-industrialising economies). Soon the West will run out of initials to describe what they must once have thought were some interesting, if not necessarily sustainable, examples of Third World progress. What the OECD underlines is that Asia has begun to enter a virile maturity, with, so far, none of the arteriosclerosis which has left too much of the West limping. Indeed, there has been a form of rejuvenation among the dragons after what appeared to be a slowing down of expansion five years ago. The key point is that the revival has not depended totally on demand from the US and Europe, although they remain some of the biggest markets for Asia's economies. This was obviously one factor, as was the strength of the yen, which both improved the relative terms of trade of the dragons, and encouraged investment into them by Japan. The trend which is now emerging is that economic critical mass is being achieved among these Pacific nations. Those who believed in the ''Pacific Century'' will not be surprised. Those who dismissed the visionaries as theorists must now recognise the facts. The supporters must also recognise that this trend is not without its dangers. Which brings us back to inflation. In Hong Kong it is already here, and too high, thanks to the distorting effects of the territory. It is probably no coincidence that Hong Kong is the laggard of the DAEs and also has an inflation rate which is already three percentage points above that of the expected average of its regional neighbours. If every nation in the region continues to accelerate, they will all reach a speed at which overheating is a danger or, as the OECD terms it, hit their ''potential rate''. In the longer term, much will depend on the contribution to the region from China, and here the OECD gives mixed reviews. Growth is slowing from a breakneck 13 per cent (that's good), but will still be above the official nine per cent target (that's not). Inflation is coming down from a first quarter level of 20 per cent, but won't hit Beijing's target of 10 per cent. That's not at all good, and what is worse is that the reforms are putting upward pressure on prices, according to the OECD. Once again, inflation remains the element which could cool the dragons' breath - but not this year, nor next.