These statistics are worthless. Slovenia and Japan make the list while having enormous suicide rate, bigger than my country (Poland, not listed). What the heck? I bet that the average citizen of Bhutan, Micronesia or Philippines is more happy than average European with debts, work pressure, noise and all the disadvantages of living in a big city.
Ask the people who made the survey about the factors. I can say that Japan has history behind it's suicide rates. Suicide used to be honorable under some circumstances, especially for samurais and generals.