6band
The chart shows the percentage of five North American lakes covered in ice during two 20-year period. The bar chart illustrates how many lakes in North America had been covered in ice from 1973 to 1992 and from 1993 to 2012 on average.
Overall, Erie had the most lakes covered in ice in both twenty-year periods. However, in Superior, the proportion had reduced significantly over time.
On the one ha...