The baby formula shortage continues to worsen as baby formula makers and the head of the U.S. Food and Drug Administration (FDA) continue to face bipartisan grilling on what led to the national crisis.  For the week ending May 22, the out-of-stock rate for baby formula rose to 70% nationwide, according to recent data by retail data firm Datasembly. It’s a significant increase from the week prior when the national out-of-stock rate for baby formula stood at 45%.