There are 72 million dogs in the US versus a few big cats. The odds of being killed by a dog are infinitesimally smaller by comparison.
There were 33 dog attacks ending in human deaths last year (2010).
As of April 24th, 2011, there have been 5 deaths.
The majority of deaths in both years resulted from attacks by pit bulls or pit bull-type dogs.
Compare this with fatal cougar attacks - 23 in a period of 120 YEARS:
“At least 23 people in North America were killed by cougars between 1890 and 2010, including six in California. More than two-thirds of the Canadian fatalities occurred on Vancouver Island in British Columbia. Although fatal cougar attacks are extremely rare and occur much less frequently than fatal snake bites, fatal lightning strikes or fatal bee stings, children are particularly vulnerable. The vast majority of the child victims listed herein were alone or accompanied only by other children.”
http://en.wikipedia.org/wiki/List_of_fatal_cougar_attacks_in_North_America
What is interesting about these statistics is the prevalence of children as victims, both of dogs and big cats.