It’s clear that the gluten-free market is still on the rise, but just how much has it grown over the past year? The National Foundation for Celiac Awareness (NFCA) requested an update from SPINS, a market research firm that covers the natural product industry.

According to SPINS, gluten-free sales totaled $12.4 billion in the 52 weeks leading up to August 4, 2012. This includes sales in all channels, including natural, specialty gourmet and conventional food and drug. The number reflects an 18% increase over the previous year, which recorded $10.5 billion in sales.

New this year, SPINS included sales of gluten-free products at Walmart, which recently released its data for use, according to SPINS. Walmart carries a variety of gluten-free products and will be the site of NFCA’s first-ever gluten-free shopping spree, part of the Grand Prize in the Gluten-Free Pantry Raid sweepstakes.

Walmart’s data account for some of the increase in overall gluten-free sales, but SPINS noted that the $10.5 billion report of the previous year’s sales has also been adjusted to reflect sales at Walmart. Therefore, the 18% increase is a true reflection of the market’s growth, according to SPINS.