Jenkins Plot is Empty

I am working with Jenkins and Lizard to report code complexity of an upcoming project. I would like to plot my code complexity with every build. However I am having some issues.

Here is my XML and my Jenkins file.

<cppncss>
    <measure type="Function">
        <labels>
            <label>Nr.</label>
            <label>NCSS</label>
            <label>CCN</label>
        </labels>
        <item name="foo( int x) at ./main.c:3">
            <value>1</value>
            <value>6</value>
            <value>2</value>
        </item>
        <item name="bar( int x) at ./main.c:10">
            <value>2</value>
            <value>6</value>
            <value>2</value>
        </item>
        <item name="main() at ./main.c:17">
            <value>3</value>
            <value>7</value>
            <value>1</value>
        </item>
        <average label="NCSS" value="6.333333333333333"/>
        <average label="CCN" value="1.6666666666666667"/>
    </measure>
    <measure type="File">
        <labels>
            <label>Nr.</label>
            <label>NCSS</label>
            <label>CCN</label>
            <label>Functions</label>
        </labels>
        <item name="./main.c">
            <value>1</value>
            <value>19</value>
            <value>5</value>
            <value>3</value>
        </item>
        <average label="NCSS" value="19.0"/>
        <average label="CCN" value="5.0"/>
        <average label="Functions" value="3.0"/>
        <sum label="NCSS" value="19"/>
        <sum label="CCN" value="5"/>
        <sum label="Functions" value="3"/>
        <average label="NCSS" value="6.333333333333333"/>
        <average label="CCN" value="1.6666666666666667"/>
    </measure>
</cppncss>

Using an XPATH parser online I am able to access the data I want. The 5 entries <average> at the bottom of the file.

Using the Jenkins pipeline syntax generator I created the following plotter.

plot csvFileName: 'plot-lizard-code-complexity.csv', group: 'Code Complexity', numBuilds: '20', style: 'line', 
          title: 'Code Complexity', 
          xmlSeries: [
             [file: 'lizard_report.xml', nodeType: 'NODE', url: '', xpath: '/cppncss/measure[2]/average[1]'], 
             [file: 'lizard_report.xml', nodeType: 'NODE', url: '', xpath: '/cppncss/measure[2]/average[2]'], 
             [file: 'lizard_report.xml', nodeType: 'NODE', url: '', xpath: '/cppncss/measure[2]/average[3]'], 
             [file: 'lizard_report.xml', nodeType: 'NODE', url: '', xpath: '/cppncss/measure[2]/average[4]'], 
             [file: 'lizard_report.xml', nodeType: 'NODE', url: '', xpath: '/cppncss/measure[2]/average[5]']
             ], 
             yaxis: 'Complexity'

I get no data into my plot, I also get no errors from the build process. I have tried this with nodeType as NODE and NUMBER.