I think this would be a better stat if we could take the money earned from the sale of the Brooklyn properties out of the equation. Then we'd get a clearer idea of exactly how much money they're making out of sales of Kingdom Halls.
Because let's be clear about this - sale of Kingdom Halls is rank theft. Members donate hard earned cash to pay for then actually build their congregation's own Kingdom Halls .
Yet incredibly Watchtower then comes along and steals them right from underneath their noses. Selling them with 100% profit, since they contributed zero towards their cost.