Creating a hierarchical table of contents using xsl:n

I'm trying to create a table of content that looks like this:

1. Fruit
1.1. Citrus
1.1.1. Orange
1.1.2. Lemon
1.1.3. Lime
1.2. Apple
2. Vegetables
2.1. Tomato
2.2. Carrot


from an xml file with this structure

<level1 title="fruit">
   <level2 title="citrus">
      <level3 title="orange"/>
      <level3 title="lemon"/>
      <level3 title="lime"/>
   </level2>
   <level2 title="apple"/>
</level1>
<level1 title="vegetables">
   <level2 title="tomato"/>
   <level2 title="carrot"/>


But I can't figure out how to make my xsl transformation write the
numbers for all the levels in the hierarchy. Right now it just outputs
the bottom level, so it looks like this:

1. Fruit
1. Citrus
1. Orange
2. Lemon
3. Lime
2. Apple
2. Vegetables
1 Tomato
2 Carrot


This is what my code looks like:

<xsl:for-each select="level1">
	<xsl:number level="multiple" count="h1" value="position()" format="1.1. "/>
	<xsl:value-of select="@title"/><br />
			
	<xsl:for-each select="level2">
		<xsl:number level="multiple" count="h1|h2" value="position()" format="1.1. "/>
		<xsl:value-of select="@title"/><br />
				
		<xsl:for-each select="level3">
			<xsl:number level="multiple" count="h1|h2|h3" value="position()"
format="1.1.  "/>
			<xsl:value-of select="@title"/><br />
		</xsl:for-each>		
	</xsl:for-each>	
</xsl:for-each>