60.
You influence those around you, change their personalities, your actions ripple through society, each action changing the world just a little bit. A single vote from a single man can be said to be meaningless in an election, it's just one in millions, but it is slightly tipping the scales in favor of one side. Each small person inputting a small percentage to change the world, change how the election is run, who wins. Each person does the same in society, each person changes the whole face of humanity by just a small bit, changing someone else's personality, a small action, just a "hi" or a "how are you", it changes people. It changes people in a small way, maybe not even noticeable, but it changes people, and the accumulation of these small changes from everyone at every time is what creates us, everyone and everything.
Everyone matters, because everyone influences everyone else.