Using XSLT to create SVG

I have an XML file that stores data about classes at a school. I'm just starting to mess around with SVG, so made an SVG file to represent the enrollment numbers in each class. Here's a shrunken version of what I came up with:

The first bar represents the 25 students enrolled in the first class and so on.

Since I've also learned some basic XSLT, I'd like to see if I can pull in those enrollment numbers from the XML file posted below instead of just putting the numbers in manually (like I did to create the image above) since that is too easy. That is where I'm having trouble. I have most of the info correct I believe, but if you take a look at my XSLT file below, you'll see I have the height of each rectangle set to 15 and I would like to multiply that by the enrollment number (so the height of the first bar should be 15*25, with the 25 being pulled from the XML file via XSLT. The second bar should be 15*20, since the enrollment of the second class is 20, and so on). I started out well and I think I'm close, but after I started adding templates, the bars disappeared. Any help would be appreciated!

Current XSLT file:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" 
xmlns:xsl="http://ift.tt/tCZ8VR">

  <!-- main template -->
  <xsl:template match="/">
    <!-- root element is svg and its namespace -->
    <svg version="1.0"
     xmlns="http://ift.tt/nvqhV5">


        <!-- Vertical red line -->
        <line x1="30" y1="35" x2="30" y2="500"
        style="stroke:rgb(255,0,0);stroke-width: 3" />
        <!-- Horizontal red line -->
        <line x1="30" y1="500" x2="500" y2="500"
        style="stroke:rgb(255,0,0);stroke-width: 3" />

        <!-- apply templates to display rectangle bars-->
        <xsl:apply-templates select="courses/course/enrollment" />
      </svg>
  </xsl:template>

        <!-- Rectangle 1 template -->
        <xsl:template match="enrollment[1]">
        <!-- Blue Rectangle 1 (341-01) -->
        <rect x="40" y="{500-@height}" width="30" height="{15*.}"
        style="fill:rgb(255,0,0);stroke-width: 3;stroke:rgb(0,0,0)" />
        </xsl:template>

        <!-- Rectangle 2 template -->
        <xsl:template match="enrollment[2]">
        <!-- Blue Rectangle 2 (341-02) -->
        <rect x="100" y="{500-@height}" width="30" height="{15*.}"
        style="fill:rgb(255,0,0);stroke-width: 3;stroke:rgb(0,0,0)" />
        </xsl:template>

        <!-- Rectangle 3 template -->
        <xsl:template match="enrollment[3]">
        <!-- Blue Rectangle 3 (341-03) -->
        <rect x="160" y="{500-@height}" width="30" height="{15*.}"
        style="fill:rgb(255,0,0);stroke-width: 3;stroke:rgb(0,0,0)" />
        </xsl:template>

           <!-- Rectangle 4 template -->
        <xsl:template match="enrollment[4]">
        <!-- Blue Rectangle 4 (368-01) -->
        <rect x="220" y="{500-@height}" width="30" height="{15*.}"
        style="fill:rgb(255,0,0);stroke-width: 3;stroke:rgb(0,0,0)" />
        </xsl:template>

           <!-- Rectangle 4 template -->
        <xsl:template match="enrollment[4]">
        <!-- Blue Rectangle 5 (375-01) -->
        <rect x="280" y="{500-@height}" width="30" height="{15*.}"
        style="fill:rgb(255,0,0);stroke-width: 3;stroke:rgb(0,0,0)" />
        </xsl:template>

           <!-- Rectangle 4 template -->
        <xsl:template match="enrollment[4]">
        <!-- Blue Rectangle 6 (385-01) -->
        <rect x="340" y="{500-@height}" width="30" height="{15*.}"
        style="fill:rgb(255,0,0);stroke-width: 3;stroke:rgb(0,0,0)" />
        </xsl:template>

           <!-- Rectangle 5 template -->
        <xsl:template match="enrollment[5]">
        <!-- Blue Rectangle 7 (413-01) -->
        <rect x="400" y="{500-@height}" width="30" height="{15*.}"
        style="fill:rgb(255,0,0);stroke-width: 3;stroke:rgb(0,0,0)" />
        </xsl:template>
  </xsl:stylesheet>

XML file:

<?xml version="1.0" encoding="UTF-8"?>
<courses>
  <course number="3221" credits="4.0">
    <title>Physics</title>
    <section number="01" delivery="Classroom">
      <enrollment>25</enrollment>
      <room>EA244</room>
      <instructor>
        <first>Herman</first>
        <last>Johnson</last>
      </instructor>
    </section>
    <section number="02" delivery="Online">
      <enrollment>20</enrollment>
      <instructor>
        <first>Herman</first>
        <last>Johnson</last>
      </instructor>
      <instructor>
        <first>Mike</first>
        <last>Miller</last>
      </instructor>
    </section>
    <section number="03" delivery="Classroom">
      <enrollment>12</enrollment>
      <room>SH102</room>
      <instructor>
        <first>Allison</first>
        <last>Sweeney</last>
      </instructor>
    </section>
  </course>
  <course number="1318" credits="4.0">
      <title>Psychology</title>
    <section number="01" delivery="Classroom">
      <enrollment>9</enrollment>
      <room>AT102</room>
      <instructor>
        <first>Mike</first>
        <last>Miller</last>
      </instructor>
      <instructor>
        <first>Alex</first>
        <last>Holmquist</last>
      </instructor>
    </section>
  </course>
  <course number="3715" credits="4.0">
      <title>Biology</title>
    <section number="01" delivery="ITV">
      <enrollment>18</enrollment>
            <room>EA244</room>
      <instructor>
        <first>Mike</first>
        <last>Miller</last>
      </instructor>
    </section>
  </course>
  <course number="3815" credits="3.0">
      <title>Calculus</title>
    <section number="01" delivery="Classroom">
      <enrollment>16</enrollment>
            <room>ST108</room>
      <instructor>
        <first>Herman</first>
        <last>Johnson</last>
      </instructor>
    </section>
  </course>
  <course number="4113" credits="3.0">
      <title>Chemistry</title>
    <section number="01" delivery="Online">
      <enrollment>20</enrollment>
      <instructor>
        <first>Mike</first>
        <last>Miller</last>
      </instructor>
    </section>
  </course>
</courses>