Creating a stacked bar graph in C#

StackedBarGraph.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Web.Helpers;
using System.Web.Mvc;
using System.Web.UI;

public class StackedBarGraph
{
  public ActionResult CreateStackedBarGraph()
  {
         //Using Web Helpers Chart methods 
         // chartType: StackedBar, StackedColumn, etc 
         
         //Writing this because no documentation or code samples on how to pass multiple values for x and y exist
    
         
         
       var key = new Chart(width: 300, height: 200, theme: ChartTheme.Green).AddTitle("Stacked bar demo")
                .AddSeries
                (
                    chartType: "StackedBar",
                    legend: "Item1",
                    xValue: new[] { "2012", "2013", "2014", "2015"},
                    yValues: new [] {34, 50, 10, 25}
                )
                .AddSeries(
                chartType:"StackedBar",
                xValue: new[] { "2012", "2013", "2014", "2015" },
                yValues: new [] {12,54,85,3}
                )
                .AddSeries(chartType: "StackedBar",
                    xValue: new[] {"2012", "2013", "2014", "2015"},
                    yValues: new [] {15, 5, 74, 32}
                    
            );
          
          
            return File(key.ToWebImage().GetBytes(), "image/jpeg");
              
        }     
  }
}

Thanks!