Gross profit $ and gross profit % for Walgreens

Gross profit for 2018 = Revenue Cost of Goods Sold = 131,537 100,745 = $30,792

Gross profit % for 2018 = Gross profit / total sales * 100 = $30,792 / $131,537 *100 = 23.41%

Gross profit for 2017 = 118,214 89,052 = $29,162

Gross profit % for 2017 = $29,162 / $118,214 *100 = 24,67%

Gross profit for 2016 = 117,351 87,477 = $29,874

Gross profit % for 2016 = $29,874 / 117,351 *100 = 25,46%

Gross profit $ and gross profit % for CVS

Gross profit for 2018 = 194,579 156,447 = $33,132

Gross profit % for 2018 = $33,132 / $194,579 *100 = 17.03%

Gross profit for 2017 =184,786 153,448 = $31,338

Gross profit % for 2017 = $31,338 / $184,786 *100 = 16.96%

Gross profit for 2016 = 177,546 146,533 = $31,013

Gross profit % for 2016 = $31,013 / $177,546 *100 = 17,47%

What do the results of this calculation mean in the context of Walgreens? How about CVS? Compare the two - why are they different (be as specific as possible).