Wales and the Southwest have experienced the biggest fall in footfall numbers in the UK.
The number of shoppers visiting stores in May fell 8 per cent compared with a national average decline of 2.4 per cent.
The only area to show growth was in the Southeast where footfall increased 0.1 per cent, according to the Experian figures.
Although footfall usually falls in May due to two bank holidays, the decline this year has been more severe than usual. Footfall at out-of-town retailers declined 0.9 per cent, which was unexpected as May is usually a strong month for retailers on retail parks, such as DIY chains.
Experian senior global economist Matthew Sherwood said: “We expect annual retail sales growth to slow over the next few months as weak disposable income growth, rising unemployment and an increase in savings take their toll on spending.
“Additionally, there is much less scope for discounting with prices low and a weak pound increasing the pressure on retailers. We expect retail sales volumes to decline on an annual basis during 2009 for the first time since the last recession.”