Figure 11.3: Figure 11.3 U.S. Geological Survey (USGS) reported hourly lake levels from November 1, 2007, through August 11, 2015, for Lake Murray, SC. There are 67,810 lake-level observations. The histogram on the left is showing the number of times the lake was at each level. The histogram on the right shows these same data as the percentage of times Lake Murray reached each level.