message: [time table] fix sorting on missing values
diff: @@ -123,6 +123,7 @@ function viz(slice, payload) {
  } else if (column.comparisonType === 'perc_change') {
  v = (recent / v) - 1;
  }
  + v = v || 0;
  } else if (column.colType === 'contrib') {
  // contribution to column total
  v = recent / Object.keys(reversedData[0])
  