You are only getting one column from the database. You'll see in the example that 2 columns are being returned, and one of them is a calculation that returns a percentage. It looks like you will need this to create the graph.

And in this section

foreach (DataRow dr in GetQuestionSummary().Rows)
    Summary summary = new Summary();
    summary.Value = dr[0].ToString().Trim();
    summary.Item = Convert.ToDouble(dr[1]);

you can see that an Item and a Value are needed. Again, you need 2 columns of data to work with.

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