Footfall in May was 0.2% down on a year ago according to the latest BRC/SPRINGBOARD Footfall Monitor.
This was marginally down on the 0.1% fall in April and below the three-month average of a 0.6% increase.
Clothing was the best performing category, reporting its highest growth since December 2011, while Food was the lowest, reporting a decline in total terms.
Footfall on the high street was 0.9% down on the previous year for May, up on April's fall of 1.4%.
Out-of-Town reported the only rise, 3.3% higher than a year ago, while footfall in shopping centers was down 1.5% on the previous year.
All regions and countries with the exception Greater London (-1.6%) West Midlands (-2.3%), East Midlands (-3.0%) and Wales (-2.6%) reported positive footfall.
Helen Dickinson, British Retail Consortium Director General, said: "This is the second successive month that footfall has eased back a touch, compared to the same period last year. However actual retail sales over the period have risen, which points to the continuing impact and popularity of online shopping particularly in non-food categories. Many retailers are increasingly adept at harnessing the internet and multi-channel innovations to get through to consumers who might not have time to travel to the shops."
"As we saw with our retail sales data released earlier this month, purchases of bigger ticket items for revamping the home and garden performed well off the back of the continued pick up in the housing market, as did sales of televisions ahead of this summer's sporting spectacles, primarily the World Cup and Commonwealth Games. Out of town shopping locations have continued to do well as a result, recording a further strong uptick in footfall."