Return Path, an email certification and reputation monitoring company, has today released its latest biannual Global Email Deliverability Benchmark (H2-2011) report. The study found that the number of emails reaching peoples inbox (globally 76.5% make it through SPAM filters) is “rapidly decreasing” (down 6% in H2-2011) and consequently “email marketers are continuing to pour money down the drain” (oh how terrible).