using preceding-sibling to calculate acummulated amount

Hi all...

I need to show in HTML a column of a table that shows the acummulated quantity... If, for example, I have:

<row>
  <total>1</total>
</row>
<row>
  <total>2</total>
</row>
<row>
  <total>3</total>
</row>
<row>
  <total>4</total>
</row>

I want to show in HTML:

1
3
6
10

I tried:
total + preceding-sibling::total

but it didn't work.

Thanks
Jaime