\begin{table}[htbp]\centering
\begin{threeparttable}
\caption{Listing-level sample attrition}\label{tab:attrition}
\small
\begin{tabular}{p{9cm}rr}
\toprule
Step & Listings & Share of initial \\
\midrule
All listings in snapshot (products table) & 124\,579 & 1.000 \\
excl. SAQ (alcohol monopoly) & 117\,102 & 0.940 \\
excl. pharmacy feeds & 115\,352 & 0.926 \\
excl. non-food categories (health \& beauty, household, pets, baby, alcohol) & 112\,233 & 0.901 \\
with at least one observed price & 111\,924 & 0.898 \\
excl. unrealistic prices & 111\,575 & 0.896 \\
… with parsable package size (unit-price / matching universe) & 66\,340 & 0.533 \\
… in a cross-banner match group (tiers A–C) & 13\,273 & 0.107 \\
\bottomrule
\end{tabular}
\begin{tablenotes}[flushleft]\footnotesize
\item Each row applies the stated filter to the previous row. Matching tiers A--C shown; the primary analysis uses A+B.
\end{tablenotes}
\end{threeparttable}
\end{table}