Pretty much everyone who works in suicide prevention (in individuals and across populations) says that reduction in access to means and methods is an important part of suicide prevention.
But it is just a part. You need the other stuff alongside the reduction of access to means and methods.
> Australia were 11.0 in 1980, [...] currently 12.0
Just checking, but are you counting the same thing over all those years? Definitions of suicide change; methods for gathering the data changes.
That makes it hard to compare rates across years.
http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/...
> More broadly, this change in administrative systems highlights how various factors (including administrative and system changes, certification practices, classification updates or coding rule changes) can impact on the mortality dataset. Data users should note this particular change and be cautious when making comparisons between reference periods. The change does not explain away differences between years, but is a factor to consider.