I would expect top gear to be direct (1:1).
MBDoc shed a little light on gear ratios. I wonder if the book I have is giving Euro ratios. I had a US 240D before my Euro model, it seemed that the Euro had a lower gear ratio (higher numerically). I thought maybe it had an optional mountain ratio. Goodness only knows, if you were driving a 240D in the mountains, you'd need all the help you could get. But maybe, the Euro cars are geared differently.