That's the problem with statistics. Dortmund takes its U23 team seriously since, at best, 2010. So, what really matters is the players coming through in the next years. Dortmund produced Erik Durm, a German NT player, via the reserve team. They produced Jonas Hofmann, a young player with regular playing time for Klopp's team, via the reserve team. They were able to secure Marvin Ducksch a loan deal to a Bundesliga 1 club through his great performances in the reserve team. And I expect Mitsuru Maruoka and Tammo Harder will be the next players in the pro team coming right out of the reserve team. Every German club has its own philosophy when it comes to the reserve teams. Leverkusen and Frankfurt even have closed their U23 department. Dortmund values the U23 highly, but only since Klopp's youth policy changes in 2010. But as usual in this sport, only very few talents really reach the top for various reasons.