“Tax shelter” has a particular meaning in the Income Tax Act. In a nutshell, it is any donation arrangement where, through accommodation of tax credits or tax deductions, individuals will receive a benefit more than the cost they've actually paid to acquire the property. It's been a big problem since about the early 2000s. They started out as art-flip arrangements. That's what they were known as. Somebody buys a piece of property for a low price and then donates it to a charity.
Over the years, they've become more sophisticated. We introduced some rules back in 2003. There were additional rules that were introduced, which are part of a technical bill that hasn't passed, but those are what you're seeing there.
There was, as you see from that chart, a high level of those types of donations in and around 2006, but through the proposed changes and CRA audit work have managed to bring that number down quite considerably.