Determine number of columns in a row for a marker

I'm working within the context of DITA and anytime a table breaks across a
page, I want to set a marker that will be retrieved in the table-head and
display the table title along with (Continued).
It's mostly working but I'm having difficulty setting fo:table-cell
number-columns-spanned.

Setting the marker within:
<xsl:template match="*[contains(@class, ' topic/row ')]" > ...
            <xsl:choose>
                <xsl:when test="count(preceding-sibling::*[contains(@class, '
topic/row ')]) = 1">
                   <fo:marker marker-class-name="continued"/>
                </xsl:when>
                <xsl:otherwise>
                    <fo:marker marker-class-name="continued">
                        <fo:table-row
xsl:use-attribute-sets="table__continued__text">
                            <fo:table-cell number-columns-spanned="{???NEED TO
FIGURE OUT HOW TO COUNT THE NUMBER OF COLUMNS}???">
                                <fo:block
padding-bottom="5pt"><xsl:apply-templates
select="ancestor-or-self::*[contains(@class,' topic/table
')]/*[contains(@class,' topic/title ')]"><xsl:with-param
name="fromContinued">true</xsl:with-param></xsl:apply-templates></fo:block>
                            </fo:table-cell>
                        </fo:table-row>
                    </fo:marker>
                </xsl:otherwise>
            </xsl:choose>

Then later the marker is retreived:
<xsl:template match="*[contains(@class, ' topic/thead ')]">
        <fo:table-header xsl:use-attribute-sets="tgroup.thead" id="{@id}">
                    <fo:retrieve-table-marker retrieve-class-name="continued"
                        retrieve-position-within-table="first-starting-within
-page"/>

Without success I've tried:
{count(preceding-sibling::*[contains(@class, ' topic/row ')])}

Any guidance would be appreciated.
Thanks!
Matt
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