Complex sentence: At peak production, a single mill at Washburn-Crosby made enough flour for 12 million loaves of bread each day, and by 1900,14.1 percent of America's grain was milled in Minneapolis.
Split into simpler sentences: At peak production, a single mill at Washburn-Crosby made enough flour for 12 million loaves of bread each day. By 1900,14.1 percent of America's grain was milled in Minneapolis.