The System Load Indicator can be installed in Ubuntu 16.10 by adding the System Load Indicator stable daily builds PPA:

sudo add-apt-repository ppa:indicator-multiload/stable-daily
sudo apt update

Now you will be able to install it with any GUI package manager / software center or:

sudo apt install indicator-multiload

Please note it should also be available in the official Universe repository and can be installed with the command above without adding the daily PPA.