Garfey, clearly there are numerous causes for distraction accidents - and I've been hit that way myself a couple of times. I'll suggest, though, that we respect the OP's intent for this thread.
As long as I can remember - and I've been driving since 1969 - alcohol has been a factor in around 50% of all motor fatalities. It goes up or down a little, but sadly, it never goes away. I taught Defensive Driving in 1972-73. At that time, not only did the 50% stat exist, there was another, even more startling stat - 75% of all pedestrian deaths involved alcohol (not necessarily the driver, by the way).
One of the better things the US has done, over the past 4 decades, is to lower the legal blood-alcohol limit from 1.0 to .8 (or .1 to .08, depending on your metrics), which is in keeping with almost all European nations (who have more than their share of alcohol accidents to deal with). Back when most states were still at 1.0, Car & Driver Magazine decided to write an investigative article. Armed with a rented test track, various configurations of orange cones, a stable of test vehicles, and what they described as "each editor's favorite beverage", they went to work. They did baseline testing on their closed course. They knocked back a couple, measured their alcohol level using Breathalyzers (would you trust Brock Yates with a needle & syringe?), and repeated the driving events. This went on for a matter of hours. By the end, they were drunk, sick, having no fun at all, and hopelessly incapable of negotiating the simplest maneuvers without murdering a few cones. During the exercise, not one of them ever hit the 1.0 limit of being legally drunk. And that's how Car & Driver Magazine became active in a campaign to lower the legal limit in all states. I've looked for a copy of that article over the years, but never found it. Somewhere in 1976, I believe.
While I was stationed in Germany, at New Year's Eve, many posts very strongly encouraged their people to plan their celebrations so that they slept over, rather than driving home. That was to protect them from themselves, and from others.
Over the years, I've lost several friends in motor accidents (always in cars, not bikes), and without having tracked it, I'd say the 50% statistic has been alive and well.