[lugged]

40-50% is perfectly acceptable for your team by the sounds of it. In other teams with varying degrees of experience and skill things are a bit more wild.

The fact that you can add tests means your code is at least somewhat scaffholdable and that is the important part for testability.

For the record I do TDD maybe 20% of the time, I mostly just use it in tough problems where I don't know what to do next.

It's a tool, not a goal.