Analysis: Like a piece in a jigsaw, the latest data release from the Central Statistics Office (CSO) fits together with pieces provided earlier this month by the Department of Finance, the Irish Intercontinental Bank, the ESRI and the Central Bank. It shows that our economy is slowing down, with GDP growth in the first quarter amounting to 2.4 per cent.

This compares with 4.5 per cent growth last year and is much closer to the rates of growth experienced by our euro-zone neighbours. Over the course of 2004 the annual rates of GDP growth declined from over 6 per cent in the first quarter to 2.3 per cent in the fourth. The first piece of the jigsaw was provided by the Department of Finance. At the start of the month it reported an exchequer surplus for the first half of 2005. But this was due to the government spending considerably less than planned on public investment. Also tax revenue growth was driven significantly by special factors, such as growth in car sales. Income corporation taxes were disappointing.

The CSO's latest data covers only the first quarter of this year, but is more complete. They estimate that non-housing construction activity fell by 18 per cent year-on-year for that period, driven largely by the government's capital underspend.

Housing construction, car purchase and spending on recreation and entertainment were important in driving first-quarter growth. Machinery and equipment expenditure was also strong, but related to the once-off large purchases such as aircraft.

The next piece of the jigsaw was a joint study of the Irish Intercontinental Bank (IIB) and the ESRI. We knew already that we were all borrowing lots of money. But the IIB/ESRI study told us why. For 60 per cent of us, it is to keep up our standard of living, while 40 per cent are borrowing for investment purposes, probably to buy cars.

Then along came the Central Bank. They - as ever - warned us that growth in personal lending was putting us at risk from future interest rate rises. But this time they were able to point out that our levels of personal debt are now the second highest in the EU after the Netherlands. Now defenders of our present borrowing levels say that they reflect a young, dynamic economy that is investing in housing and infrastructure.

Levels of personal debt may indeed - just - be sustainable. But the rate at which it is increasing is not, at least in the long-run. According to yesterday's CSO data, growth is coming from sources increasingly associated with personal lending. If growth rates in personal lending are not sustainable, what does it say about our long-run growth potential?

Finally, the Central Bank also published its latest forecast of the economy yesterday in its Summer Quarterly Bulletin. It predicts GDP growth of 5.5 per cent this year. But the CSO data came too late to be reflected in that forecast. The government's 2005 GDP forecast - 5.1 per cent - also excludes the latest CSO data. Both will have to be revised later in the year, most likely downwards and any shortfall in economic growth is likely to be mirrored by tax revenue shortfalls, giving the Government less room for manoeuvre in the next budget.

Admittedly Gross Domestic Product figures distort the picture of our economy by including the economic impact of multinational companies. Strictly speaking, we should look at Gross National Product (GNP) which adjusts for this effect. The multinational sector performed poorly earlier in the year and GNP grew in the first quarter by a steadier 4 per cent. But the strength of GNP growth relative to GDP serves to underpin the increasing reliance of our economy on domestic factors, which are in turn linked to growing debt. And the weakness of our export sector applies equally, if not more so, to our indigenous sector as to multinationals. Yesterday's Central Bank Bulletin contained an article by Mark Cassidy and Derry O'Brien on the continuing decline in our indigenous manufacturing competitiveness. Yesterday's data from the CSO backs this up. Exports of goods and services fell by 1 per cent in the first quarter of this year.

There are more pieces of our economic jigsaw to come. If they are anything like what we got this month, the picture of our economy at the end of the year will be different to what it looked like it would be at the start.