[linuxftw]

That could also be explained that everyone who wanted to kill themselves (WW2 veterans) had already done so. Suicides being 1/3 lower in the 70s than the 50's and 60's seems expected.

[loeg]

Coal gas purportedly has much higher levels of carbon monoxide than natural gas, which would be sufficient.

[linuxftw]

I'm just talking about the connection to the overall suicide rate. Obviously if natural gas doesn't kill you, or as quickly, that method of suicide will go down. But the overall rate can be explained by many other phenomenon.

[saberdancer]

Yes but there is a much larger effect on gas oven suicides than overall.

Suicide prone population dying out would not cause one type of suicide to reduce in a much quicker rate - as is implied here.