The German discounters, which were originally viewed as a niche part of Ireland's grocery market, have officially become mainstream. New data, which has been seen by the Sunday Tribune, shows that almost 85% of households are visiting the discounters as they shop around for the best value.

It's the first time that more households shopped at the discounters over the past year than in Dunnes Stores (83.2%) and means that Tesco (91.9%) is the only retailer to outrank them. The figures, which are for the 52 weeks ending 12 July, showed that 75.6% of households have shopped in SuperValu and 50.9% have shopped in Superquinn, up from 45.4% last year.

TNS Worldpanel, which compiled the data, says that the fact that all of the retailers increased their footfall shows households are becoming more aware of promotional activity and shop around more as a result, spending less in each individual shop. As a result the average basket size has dropped from €39.40 to €33.50 in Tesco and from €37.80 to €33.50 in Dunnes.

"We see the average consumer shopping 59 times in the latest 12 weeks compared to 57 times last year. Their spend on each visit has dropped from €24.60 to €22.40," said David Berry, business group director at TNS Worldpanel. In particular, Dunnes, Tesco, SuperValu and the discounters are seeing higher footfall as people shop around.

As retailers such as Tesco focus on 'permanent price reductions', the discounters have responded by starting additional promotions and this has helped them to continue to gain ground on the main players in the market. Their share of the total grocery market for the three months ending 12 July was 8.5%, its highest ever, and a 14% increase on the same figure for the preceding 12 months. Aldi has seen sales growth of 20% in the last three months, while Lidl has seen 10% growth.

"The discounters have managed to continue their store expansion this year which has helped them recruit consumers," Berry said.

By contrast, the traditional supermarket groups have all seen their market shares fall in the last three months. Tesco's market share now stands at 25.6%, Dunnes' stands at 23.6%, SuperValu's is 20.5% and Superquinn's market share is 7%.

Some of the supermarket groups have responded by pushing their promotions hard via advertising; 26.9% of groceries bought in Dunnes Stores are going through "on deal" and nearly one in four grocery goods in Superquinn are bought in this manner.

Tesco has reduced the volume of its sales via promotions but this is attributable to the price cuts it introduced via its 'Change for Good' campaign to cut prices for shoppers. As a result, the total percentage of grocery spend on promotional items has actually fallen from 20% to 19% in the past three months.

Symbol groups, which have a reputation for being more expensive, have also lost ground, with their share of the market over the past year down from 6.1% to 5.6%. They have responded to this in recent months, with Musgrave's Centra launching a range of low-cost items and Spar stocking more and giving additional promotion to its own-brand goods.

Cross-border shopping remains popular but Tesco's and Dunnes' price cut campaigns seems to be having some impact. Sainsbury's and Asda have seen their share of the market in the Republic fall from 2.9% for the three months ending 17 May to 2.6% for the three months ending 12 July. Nevertheless, on a 12-month basis, Asda and Sainsbury's performance remains strong, up from 0.8% to 2.2% year on year.

TNS Worldpanel's research also shows that price reductions mean the value of the grocery market has dropped by 3.3%, although volumes are continuing to grow as customers opt not to eat in restaurants, and cook at home instead.

Customers are also buying more ambient food such as canned products and dry goods like rice and pasta because of their long shelf life. The trend is accentuated by the fact that bulk buying of goods on promotion is becoming more popular, driving sales forward by 4.6% in the last year.

Alcohol sales are also up by 1.3%, presumably because more people are staying away from pubs. Reports that some publicans might put up the price of drink after a court decision to remove their price freeze are likely to increase these figures.

In contrast, spending on healthcare products has slumped by more than 8%, while sales of frozen good has also fallen slightly.

TNS Worldpanel's figures are based on a basket of more than 200 grocery categories and are not taken from total till receipts. Their figures include only those goods taken home by customers, and do not take into account convenience purchases.