Anyway, there are indeed statistics that point to the conclusion that texting and driving is at least comparable to drunk driving in terms of fatalities caused per year.
If researchers at the Cohen Children's Medical Center (Long Island) are to be believed, more than 3,000 teenagers are killed in texting-related accidents in the United States every year. If that's true, then practice of texting while driving is more serious than driving under influence, which―according to the CDC―results in 2,700 teen deaths every year.
Again, I think that the penalties for texting and driving are so relatively minor compared to DUI penalties because lawmakers haven't faced an undue amount of pressure from lobbying groups such as MADD. Dangerous driving practices need to be curbed by serious deterrents, but that does not mean that penalties need to ruin people's lives. Furthermore, while I lack proof, I have the impression that drunk driving has NOT decreased in the past 20 or so years since the penalties have been made more and more severe along with the max legal Blood Alcohol Content being decreased.