According to CDC, their were 2,596,993 deaths in 2013 in the US. In 2012, according to the FBI their were 8,855 gun homicides. One year separating these facts, but you can guess that the trend will follow over a single year time period. LESS THAN 1%
The vast majority (http://www.cdc.gov/nchs/fastats/deaths.htm) are basically various diseases. Most people would be in favour of trying to reduce preventable deaths, particularly where innocent bystanders are involved - like mass shootings and car crashes.
CIA world factbook. UK ranked higher(60th) in death rate overall than US(93rd) as of 2015. Oh yeah not to mention other "gun free safe zones" such as Canada(81st), Spain(68th), France(65th), Sweden(59th), Japan(54th). So on and so forth...
Looking at the murder rates per 100,000 people listed here https://en.wikipedia.org/wiki/List_of_countries_by_intentional_homicide_rate#By_region, the United States of America doesn't do too well, with a value of 3.9.
To compare with the examples you cited: Canada has a rate of 1.4, Spain of 0.7, France of 1.2, Sweden of 0.9 and Japan of 0.3.