We all currently use IPv4 address, at least most of us. IPV6 addresses are used by some Bit torrent client but they are still redundant as the machine using IPV6 address also Have IPV4 address.
As of January 1st, 2011; we have about 496 million unused IPV4 addresses. And in year 2010 we used about 225 Million IPV4 addresses. These number suggest that we will run out of the IPV4 addresses in 2 years but at the rate we are growing this will happen much sooner. All these stats comes out from IANA global pool of IP Address.
Current population of earth is about 7 Billion and the rate by which internet users are increasing and everything is going for computerization the supply of IPV4 addresses is going to run out very soon. There is no way we can add number of IPV4 address. They will remain constant no matter how many of people we add on Planet earth.