Apparently BP produce a yearly very data heavy review of the state of world energy. For those who want to wade through it I have produced it below and the original can be downloaded from here.
The review contains the chart below which looks at the historical price of crude and drops in some interesting historical events to add context.
However, due to publishing constraints the chart doesn’t contain the recent collapse in crude prices so I took some of the data and put in a nominal 2014 closing price and last nights closing price. What it shows is that whilst the current drop is impressive it is not as impressive as it could be.