Complex sentence: By the start of 1989, the chain had slowly grown to about 15 stores, and by late 1992, it had grown to 50 locations in seven states, and its growth continued to accelerate.
Split into simpler sentences: By the start of 1989, the chain had slowly grown to about 15 stores. By late 1992, it had grown to 50 locations in seven states, and its growth continued to accelerate.