Compute trend percents for the above accounts, using 2017 as the base year. For each of the three accounts, state whether the situation as revealed by the trend percents appears to be favorable or unfavorable.

\begin{tabular}{lrrrrrrrr} & \multicolumn{1}{c}{2021} & 2020 & \multicolumn{1}{rr}{2019} & \multicolumn{1}{r}{2018} & \multicolumn{1}{r}{2017} \\ Sales & $282,880 & $270,800 & $252,600 & $234,560 & $150,000 \\ Cost of goods sold & 128,200 & 122,080 & 115,280 & 106,440 & 67,000 \\ Accounts receivable & 18,100 & 17,300 & 16,400 & 15,200 & 9,000 \end{tabular}