select "year" || '-' || "month" as year_month, new_datasets, new_tables, rows_added,
  SUM(new_datasets) OVER (ORDER BY "year","month"
    ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS new_datasets_cum,
  SUM(new_tables) OVER (ORDER BY "year","month"
    ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS new_tables_cum,
  SUM(rows_added) OVER (ORDER BY "year","month"
    ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS rows_added_cum
from @blt.catalog_metadata.monthly_catalog_stats
order by year, month