Do it Best Corp. announced Sunday at its fall market that sales grew 11.2% during the fiscal year ended June 30, 2012, from a year earlier to total $2.68 billion, its biggest increase in eight years. The company credited operational efficiency and member optimism for the growth.

The Fort Wayne, Ind.-based buying group also awareded $115.7 million in member rebates for the year, up 9.4% from a year earlier. This is the ninth consecutive year that member rebates have topped $100 million.

“The strength of our rebates comes not just from increasing top-line sales but from keeping bottom-line costs down as well,” Do it Best Corp. chief operating officer Dan Starr said in a statement. “We do this by maintaining the lowest cost of operations and overhead in our industry, including zero long-term debt. We know that by being as efficient as possible, we can share more in rebates with our members, just as we’ve done again this year.”