There is no way to estimate how many suicides occur in the U.S., much less in the world, but we do know there are millions.
Many "accidents" reported by the law enforcement agencies are not accidents at all, but are suicides. A kid drives his car into oncoming traffic and dies. The police report it as an "accident." Later, they find a suicide note. The kid actually deliberately killed himself. The same applies to falls off tall buildings, cliffs, drowning, etc.
The same even applies to drug and alcohol abuse. A kid who uses drugs is killing himself by degrees.
There is a growing concern among cops about "suicide by cop." A kids will place himself into a confrontation with the police, pretend to draw a gun, and, bang! The cops shoot him. Later they find a suicide note. They find no gun. The kid has killed himself "by cop."