Recycling allows us to reuse the materials that have been extracted from the environment to make plastic, rather than just put them in landfills or incinerate them - which creates problems of pollution as well as being a waste of resources. However, the amount of plastic that can be recycled and that actually gets recycled is relatively low.
There are six different types of plastic - PETE (polyethylene terephthalate), HDPE (high density polyethylene), V (vinyl), LDPE (low density polyethylene), PP (polypropylene), PS (polystyrene) - and the a 7th category for other and composite types. The New Plastic Economy have put together a great infographic that outlines some of the common uses of these different plastic types.
The Ocean Conservancy has also put together a great guide on plastic types and their recyclability. It's just the right size to print out for your wallet.
According to the New Plastics Economy report:
According to an EPA report released last year, in 2013 the highest national recycling rate was 63%. This covered all kinds of recycling, and not just plastics.