Just as the total population of illegal immigrants in the U.S. has declined since 2007, the proportion of illegal immigrants in the workforce has also declined; in 2012, illegal immigrants made up 5.1% of the U.S.'s civilian labor force.
Iron Ore is a common ore found almost everywhere in a Minecraft World. Iron ore generates around and below sea-level in the Overworld. It is a crucial material to gather during the early stages of the game, since it can be made into an iron pickaxe capable of mining all types of ores (including diamond). Every Iron Ore block contains enough iron to make one Iron Ingot, when it is smelted.
In Beta, iron ore requires a stone, iron, or diamond pickaxe to successfully extract. Iron ore is often used in traps as it can be mined and replaced in it's raw form. A list of craftable items can be found here. Iron ore can also be found on the surface, but very rarely.