The convenience store industry is static in terms of total numbers, but within the sector there are a number of dynamic changes taking place. David Rees reports

The scale of multiple development has been revealed once again with the publication of the annual Grocery Retail Structure, a joint project by industry think tank IGD and William Reed Business Media, publishers of Convenience Store and The Grocer.

Despite the convenience format being widely trumpeted as the fastest growing and most dynamic grocery store offer, this year's figures show that the sector enjoying the biggest increase in outlet numbers was the supermarket format, with the Big Four Tesco, Sainsbury's, Asda and Morrisons and the discounters completing significant store developments.

But that doesn't mean the multiples weren't active in the small store sector as well. Nearly three new Tesco Express outlets were opened every week last year as the chain added 145 outlets, an annual expansion rate of more than 15%.

Despite being a sector in decline in recent years, unaffiliated independent c-stores remain numerous, with more than 20,000 still operating. In fact, the reduction in numbers of 3.4% is the slowest rate of decline for five years, suggesting that the stronger stores are enduring and are continuing to meet their customers' needs. Net recruitment into the symbol sector from the unaffiliated sector also fell, with the total number of symbol group stores growing by 2.9%, a marked slowdown compared with the 7.8% increase experienced in 2009-10.

Within symbols, Booker's Premier has overtaken Spar to be the biggest symbol group by store numbers. The wholesaler has been particularly effective in recruiting stores to its small 'Express' format, more than doubling membership numbers to 463 at the time the survey was completed. Nisa and Mace also proved particularly successful in signing new members to their fascias.

The supermarket channel saw the greatest increase in store numbers of any of the major grocery retail sectors, up 4.8% to 8,545. The Big Four multiples all increased their estates in the past year, but there was also a noticeable increase in outlets with a strong discount offer, with B&M Retail, Poundland and Wilkinson all opening significant numbers of new stores.

Within the forecourt sector, consolidation of ownership is continuing with a decline in the number of independent operators and a growth in the sites under the ownership of dealer multiples. Traditional retail specialists continue to decline, with a marked drop of 4% in the number of CTN outlets. Both large chains and independent CTNs saw a reduction in store numbers, demonstrating once again that the broader range available within the convenience store format is generally proving more appealing to shoppers.

The specialist off licence channel has seen a succession of large chain collapses in recent years, but store numbers stabilised during 2010-11, supported by growth in the Bargain Booze estate and a recovery in the number of independent off licences.

See over for the detail from this year's Grocery Retail Structure.