We have similiar numbers. 80% from our website and the remainder are referrals. We did away with direct mailers mainly because of the hassel (high cost of postage with low return). However, we will do a small mailing in the fall months offering a discount to current customers only so that our calender is full right up to winter.
When we get a customer call, I always ask how they heard about us. Most of the time it’s a referral, a large amount are from search engines.
I’ve seen lots of guys out there with good sites getting barely any sales from the site because no one knows it exists. We get lots of leads from our web site because we take web site promotion really seriously. (doesn’t hurt that our site name is ridiculously easy to remember).
If your just starting out though you have a long up hill battle ahead for getting organic site visitors (people who find you with a search engine). Google adwords is a good start. Focus on your local market, don’t ever try to steal the market for a generic term like “Window Cleaning” - pretty much a waste of time. Go for local terms like “storm window cleaning in Flagstaff” or even narrow it down to the neighborhood you work in, like “window cleaning riverdale”. You’ll pay less for promotion and get more results.
BTW love the website name. Can’t get any better then that. 
But I can’t reinforce what you are saying even more. When it comes to your focused keyword, without a doubt target local. No one wants a customer from the next state, unless it’s a 20 minute drive. I get calls all the time from SEO companys trying to hit me with the standard line “You are not listed for window cleaning on google” when I respond that I don’t care they are shocked. Honestly some get nasty as if I have no idea how much business I’m losing. When I tell them to do a search for “new jersey window cleaning”, I then ask them to read off the list of results. I am #2 and #4. 1/2 the time they dont even get it. They dont even know those are my sites. I then ask them if they even know the name of my company? When they look on their call sheet and then the results again the bell goes off and they hang up.
Again target your customer, you will have a better chance of landing the sale. Tradtional form of advertising are secondary in todays world. The internet is the #1 form for reaching a customer. Even more so when you look at the ROI from it. I don’t understand why there are still so many companys not using it. I looked in my phone book the other day and there has to be at least 30 companys with either no web address listed or you can’t even find them on a search engine by typing their company name. And that’s really stupid.
