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Businesses that only export to the Republic of Ireland account for almost a third of Northern Ireland exporters.

That is what has been suggested by analysis from the Office for National Statistics (ONS).

The ONS has examined the main characteristics of Northern Ireland's trade in goods using experimental statistics for 2012 to 2016.

The figures show that more than half of goods exports went to two countries - the Republic of Ireland and the US.

However the rest of the UK is Northern Ireland's biggest external market. Republic of Ireland-only sales account for a third of NI exporters

'Brexit debate'

Sales to Great Britain are worth one-and-a-half times the value of all Northern Ireland exports and nearly four times the value of exports to the Republic of Ireland in 2016.

The ONS also cautioned that a significant number of small exporters to the Republic of Ireland and the EU may have been omitted from the report as they do not reach the threshold at which their trade information is officially collected.

The patterns of trade between Northern Ireland and the Republic of Ireland have formed an important part of the Brexit debate.

In the event of a no-deal Brexit, industries that have extensive cross-border supply chains could be seriously damaged.

The ONS report highlighted that the Republic of Ireland was the most important export destination for food and live animals from Northern Ireland.

Food and live animals represented around 33% of the total Northern Ireland exports going to the Republic, of which the top sub-category was milk and cream products.

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The report also shows that the biggest proportion of two-way cross border trade in similar products was in food and live animals, suggesting integration of supply chains in this category.

In the event of a no-deal, which involved trading on World Trade Organisation (WTO) terms, agrifood products would face steep tariffs.

Agrifood is more important to Northern Ireland than the UK as a whole.

In 2016, food and live animals exports from Northern Ireland accounted for about 14% of goods exports, whereas the same category accounted for less than 5% of the total exports from the UK.

The report finds that Northern Ireland follows general international patterns of which companies export.

Most exporters are small businesses (less than 50 staff) and sell a small number of products to a few markets.

Image copyright Getty/agafapaperiapunta Image caption In 2016, food and live animals exports from NI accounted for about 14% of goods exports

However export volumes overall are dominated by a few extremely large exporters with a wide product and market scope.

In 2016. 25% of Northern Irish exporters were exporting only one product, whereas only 0.4% exported 30 products.

The ONS says this indicates a very high specialisation or low diversification amongst a quarter of Northern Irish exporters.