Causality is always challenging in these situations, but I think the fact that we have a robust anti-spam legislation that has significant compliance requirements for all senders is a useful mechanism to be able to highlight that spam is important and that we want to cut it down. It's not directly attributable, but one can see that pre-CASL and post-CASL there has been significant progress.
On September 26th, 2017. See this statement in context.