The monthly data shows that there has been a dramatic shift toward restaurant spending in the last 10 months, and there are two major contributing factors to this change.According to the National Restaurant Association (NRA), restaurant sales in December 2014 surpassed grocery stores' monthly sales for the first time on record. Preliminary data had indicated this historic sales re-balancing, but it was officially confirmed last week by the U.S. Census Bureau's revised Estimates of Monthly Retail and Food Services Sales by Kind of Business report. The monthly data shows that there has been a dramatic shift toward restaurant spending in the last 10 months. Grocery store sales still exceeded restaurant sales by $1.6 billion in June 2014, but t...