An unrelenting economic downturn that’s spawned a vast base of value-seeking shoppers hindered discernable gains for supermarkets, PG’s research found. Supermarket sales reached $437 billion in 2009, adding $7 billion to the tally for the year, according to results of Progressive Grocer’s 63rd Annual Consumer Expenditures Study. This modest 1.6 percent comparative overall sales gain from 2008 represents the first time in five years that supermarkets failed to exceed the gain of the previous year, as a result of one the most challenging economic cycles in recent memory.