How can I get `pip install`’s download progress?

At least pip9 has -v option which prints debug msg during installation of the package.

$ pip --version                                                                                                                                                                                                                 
pip 9.0.1

Help:

$ pip install --help
..
..
-v, --verbose               Give more output. Option is additive, and can be used up to 3 times.

Usage:

pip install -r requirements.txt -vvv