How to sum a number on the retrieved value on chart xsl

Summary

How to sum a number on the retrieved value on chart xsl

Content

How to sum a number on the retrieved value

 

<RowLabels>

        <Label><xsl:value-of select="YRE"/></Label>

</RowLabels>

 

 

<Label><xsl:value-of select="YRE"/></Label>

retrieved value 2019

i want it to be

2020

 

<Label><xsl:value-of select="YRE + 1"/></Label>