Difficult to get but "Republicans & Imperialists: Anglo-Irish Relations in the 1930's" by Deirdre McMahon is the only study of the Economic War that I have seen. In the back there are charts on the Imports and Exports of the Irish Free State/Éire during this period:

In the first half of 1931 total Irish exports were £19.9 million, of which £17.3 went to Great Britain and £1.9 went to Northern Ireland. By 1939 this figure had fallen to a total of £11.3 million, £9.3 to GB and £1.1 to NI.

Total imports in 1931: £25 million, £17.7 from GB and £2.5 from NI. By 1939 this had fallen to $21 million but now just £11.2 came from GB and imports from NI had collapsed to £382,000. Imports from other countries almost doubled in the period from £5 to £9.2 million.

Ireland became self sufficient in a number of areas in this time. The hardest hit British exports to Ireland were Grain and flour (1931: £2.1 million, down to £200,240 by 1939), Food and drink (£2.5 million, down to £1.1 million) and Apparel (£3.7 million, down to £657,927). A number of companies in Britain were so dependent on the Irish market that they moved to Ireland during the Economic War which accounts for some of the decrease. When tariffs were ended these companies remained and it was difficult for Britain to get back into industries that had became self-sufficient in Ireland.

The hardest hit section of the Irish economy was agriculture. In 1931 Cattle exports were worth £7.4 million, down to £1.8 million in early 1934 but 'recovering' to £4.3 million by early 1939. Butter went from £1.4 million to £500,000 in 1934, was back to £1.4 in late 1938. Pigs dropped from £1.1 million to just £65,000 in 1937 and were still only at £186,000 in 1939.

It's hard to break an economy that doesn't really exist! There are stories of trains running late due to switching to turf as the slogan "Burn Everything British But Their Coal!" took hold. Black Bread also became common, explained above by the drop in grain and flour imports from Britain. The Economic War badly hit Northern Ireland's economy, which was heavily dependent on cross border trade and probably had a worse over all effect on Britain than it did on Ireland. The country became self-sufficient in a number of vital areas, especially food production, on the eve of The Emergency (otherwise known as the Second World War). The British had hoped that the tariffs would bring down the Fianna Fáil government of Éamon de Valera; while he did lose his overall majority he was still able to form a minority government after the 1937 election. With pressure mounting the British negotiated a return to normality which included the return of the Treaty ports, another event which contributed to Ireland being able to remain neutral during The Emergency.