Verisign have published data which shows a correlation between the increase in the price of bitcoin and an increase in the registration of domain names containing the keyword Bitcoin. The data also provides insight in the the total amount of domain names registered which contain the keyword Bitcoin since 2009, which is as follows:

2009 – 4 domains registered.
2010 – 295 domains registered.
2011 – 4,572 domains registered.
2012 – 1,734 domains registered.
2013 – 23,226 domains registered.
2014 – 15,232 domains registered through to 18th of August.

The bulk of these registrations occurred during bitcoin price bubbles.