Interpret the changes in these risk ratios during the three-year period, indicating any areas of concern.

\begin{tabular}{|l|l|l|l|} \hline Risk Ratios & 2019 & 2020 & 2021 \\ \hline Current ratio & 0.92 & 1.06 & 1.2 \\ \hline Quick ratio & 0.59 & 0.75 & 0.93 \\ \hline Operating cash flow to current liabilities ratio & 85.20% & 23.60% & 77.30% \\ \hline Accounts receivable turnover & 33.7 & 26.7 & 31.9 \\ \hline Days account receivable outstanding & 11 & 14 & 11 \\ \hline Inventory turnover & 5.8 & 5 & 5.5 \\ \hline Days inventory turnover & 63 & 73 & 66 \\ \hline Accounts payable turnover & 7.3 & 7.1 & 8 \\ \hline Days accounts payable outstanding & 50 & 52 & 46 \\ \hline Net days of working capital financing need & 24 & 35 & 31 \\ \hline Liabilities to total assets ratio & 132.40% & 126.60% & 116.90% \\ \hline Liabilities to shareholders' equity ratio & 408.50% & 476.60% & 690.70% \\ \hline Long-term debt to long-term capital ratio & 226.20% & 213.70% & 164.00% \\ \hline Long-term debt to shareholders' equity ratio & 179.20% & 188.00% & 256.20% \\ \hline Interest coverage ratio (net income basis) & 14.5 & 3.7 & 12.4 \\ \hline Interest coverage ratio (cash flow basis) & 12.6 & 3.7 & 10.6 \\ \hline Altman's Z-score & 4.1 & 2.55 & 3.49 \\ \hline Probability of bankruptcy & 0.10% & 6.11% & 0.64% \\ \hline \end{tabular}