I have a few shares, and it's done pretty well, but I don't know if I'd call it "recession proof". It took a pretty big hit from around November, 1999 when it peaked out around $45/share, dropping to around $13-14 in early 2003. At least, according to the chart on Yahoo Finance.
I forget now when I first bought it, but I remember it had been because of a pretty high dividend. Maybe around 2005-2006, I think? But at some point, the dividend was either cut, or the share price went up faster, so the yield didn't keep up. I want to say it was paying around 4-5% at one point.
It did weather the Great Recession relatively well, though. It peaked out around $65/sh in August of 2008, and the lowest it got to was around $52. It did that several times, including around the March 9, 2009 official bottom.
But, it's around $175 today, and has a yield of around 2.6%. So, it's done pretty good. The dividend has also been pretty consistent about going up every year, too.