Nucor Corporation produces steel and steel products at its eight mills and is a major recycler of scrap metal. The following data relate to Nucor for four years. In $2017,$ Nucor$$s net income was higher by $$175\mathrm{.}2$ million because of a one$-$time effect of the Tax Cuts and Jobs Act.

Nucor Corporation

$($$ in millions$)2015201620172018$

Total assets $ $14,327\mathrm{.}0$ $ $15,223\mathrm{.}5$ $ $15,841\mathrm{.}3$ $ $17,920\mathrm{.}6$

Common stockholders$$ equity $7,849\mathrm{.}98,254\mathrm{.}79,084\mathrm{.}810,202\mathrm{.}0$

Total debt $4,388\mathrm{.}54,357\mathrm{.}13,795\mathrm{.}14,291\mathrm{.}1$

Sales $16,208\mathrm{.}120,252\mathrm{.}425,067\mathrm{.}3$

Net income $900\mathrm{.}41,380\mathrm{.}62,481\mathrm{.}1$

Interest expense $169\mathrm{.}2173\mathrm{.}6135\mathrm{.}5$

Assumed marginal income tax rate $0\mathrm{.}370\mathrm{.}370\mathrm{.}23$

Source: Nucor Form $10-$Ks for $20152018.$

Required:

In the following analyses, eliminate the one$-$time net income effect of the Tax Cuts and Jobs Act on $2017$s results.

Calculate Nucor$$s ROA for $2016,2017,$ and $2018.$

Decompose ROA into operating profit margin and asset turnover components.

Has Nucor$$s profitability changed over the three years?

Calculate the rate of return on common stockholders$$ equity for $2016,2017,$ and $2018$