I've lived here since April of 2007 and at first I didn't hear it at all. Little pieces started to pop up here and there sometimes resulting in confusion. Now I hear it everywhere and even fear I'm starting to lean towards the Pacific Northwest Accent.
Here's a great clip from NPR about it.
I hear it every time I go to the grocery store. The lady asks me "Would you like a beg?" as she's ringing me up.
A friend was telling me about Angle Lake and I was googling "Engle Lake" and couldn't find where she was talking about.
I hear about bands going on tore, or toreists visiting the city. Though I suppose I might be the slightly weird one here as I pronounce tour with two distinct syllables as in TOO-er. I blame being taught to speak English by French people. I also get called Canadian sometimes for pronouncing couch like COW-ooch. I do NOT however say Aboot.
People think me profusely when I do them a favor.
The worst was when I was in a play with a lovely woman named Jan. Every time someone would call her name, I would hear "Hey Jenn!" and got really confused when they weren't talking to me.
Now that I hear it so distinctly, it has become a lot easier to pinpoint who is from here and who is a transplant. Since California is the naughty C word I try not to mention too much that I'm from there but perhaps my big wide A's give me away. "Oh Thaaaaank you, I don't need a bAg!"
Who knows, after another decade of living here I might start putting my thengs in begs more often!