How do I install the latest Nvidia drivers via the Additional Drivers tool?

Well obviously I can do it manually, I was just wondering why aren't these drivers available through "Additional Drivers", and why are the versions available there outdated.

Drivers in the Additional Tool will never be updated to higher versions unless there is a very big issue with them. You need to either add the PPA or update manually.

Upon a Ubuntu release packages are frozen in time only to be updated in case of major problems and bugs. Adding this PPA will update your drivers to the latest versions using packages packed by the Ubuntu team.

The System 76 folks maintain a PPA with just the nvidia drivers in them, so you can use this for just about any machine with an nvidia driver. The nice thing is they keep this PPA up to date with the latest upstream nvidia driver, making this PPA ideal for gamers.

If you already have the drivers installed in your system via the Additional Drivers tool

Add the System76 driver PPA (that includes Nvidia drivers)

sudo add-apt-repository -ys ppa:system76-dev/stable

Update and upgrade

sudo apt-get update && sudo apt-get install system76-driver-nvidia

Then either restart the X server or reboot.

How to remove/uninstall these drivers

Install ppa-purge

sudo apt-get install ppa-purge

Purge the system76 team PPA

sudo ppa-purge ppa:system76-dev/stable

Since it's an old (2015) question the previous answers are a bit outdated. The system76-dev/stable ppa does not seem up to date. Proprietary NVIDIA drivers are removed from bleeding edge xorg-edgers PPA but can be found now in the graphics-drivers PPA.

sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt-get update

https://launchpad.net/~graphics-drivers/+archive/ubuntu/ppa