@Lash,
When looking deeper into how countries across the planet were doing, I did notice that there are other places too, which, have had increases. Albeit not as much as the U.S.; However, it's occurring.
Focussing in on the U.S. though, the reasons are many. Some right in front of our eyes. Yes, I'm referring to the computers and smartphones. They have not only brought about isolation; they have also brought cyber-bullying. A number of people here in the U.S. left notes indicating that was the deciding factor.
Of course there is also the constant need to try and keep up with everyone else. Not to mention the shaming which takes place if a person fails to do so. Shaming of course is a form of bullying.
Increased drug usage, both legal and the illicit. Those tiny little pills screw with the brain and thinking. They clear away our freedom. They take away our realization that there are family and friends who care. People who will be devastated by the sudden loss.
Some medications prescribed to battle depression have the deadly side-effect. Cymbalta for example can increase suicidal ideations for some. That one of i know of personally as it was prescribed for me for a separate medical matter.
Then there is the continued discussion of physician assisted suicide for health reasons. A person near the ledge, may figure if it's acceptable for a person with a terminal illness or who has a handicap or sustained injury making their quality of life so dreadful, then they too should have such a right. To the suicidal person, the mental pain they are enduring is just as life altering.
Wanting to get out of the world on one's own terms, before the world kills them.
So many reasons. To answer the question of 'why?', I can only say, I wish I knew and that everyone else did as well. Maybe then, it could be worked on.