Well i live in an area where i don't need to lock my house
http://www.aic.gov.au/statistics/homicide.aspx
It doesn't go back that far but i see no incredible upward trend in the past 15 years
Gun homicides have dropped infact since the early nineties
Also
http://www.abs.gov.au/ausstats/[email protected]/Lookup/4524A092E30E4486CA2569DE00256331
is an interesting read