SAT Inferences Question

Days per Winter That Lakes Have Surface Ice It is common for freshwater lakes near or above a latitude of $45^{\circ }$ north of the equator, like Lake Stechlin in Germany, to accumulate surface ice in winter. A study from 1980 to 2006 showed that, in general, the number of days per winter that such lakes have measurable amounts of surface ice is declining. However, a researcher claimed that some lakes have instead seen an increase in the duration of ice. Which choice best describes data in the table that support the researcher's claim?