This is one of those question which can come up quite often if you are ever at a dinner party and you make the claim that people can still grow taller even after their have reached physical maturity.
Usually the first question is “how is that possible?” to a “tell me more about this idea/method/technique” to a “can this method work on anyone?” The last question indicates two things. The first one is to test to see if you, who made the outrageous claim that people can still increase their height, is full of crock and bs, or whether you might even be crazy to make the claim. They are essentially testing to see how credible you and the idea sound.
The second intention is often to see if they qualify to be able to get the technique done on them. They want to see whether they are in the group of the general population that can get it done. Again, they are still testing your credibility. People these days are not stupid. Most people, especially men, refuse to believe in anything that they can not see with their own eyes or touch. While women can be slightly more lenient and choose to believe that such things are true and can exist, men are known for their hardcore, no-nonsense approach to how they view the world. As a male, and as a person who was raised in a very scientific and pragmatic family growing up, I am not going to tell any type of lie, exaggeration, or hype on any height increase technique.
My answer to the question “What percentage of the general population can increase their height?” is that I would say It really depends on 2 main factors. The first factor is how much are people talking about when they refer to an increase in height. The second factor is what type of lifestyle do the people who want to increase their lifestyle have at the current time.
The first factor really means how much height difference are the people talking about when they talk about height increase. Overall, many people can achieve around 1 inch of extra height if they followed a program which involved stretching, strengthening their core muscles, and learning how to move and stand properly from the Alexander Method.
The 2nd factor means that people who are not regular exercisers and who don’t take care of their body are more likely to notice dramatic results. One thing to note is that in terms of natural height increase, most people never fully reach the maximum potential that their body and bones allow them to be. People who live in the developed cuntries spend a lot of time in front of the computer. The small screens and small fonts causes eye strain and increased possibility of myopia (and maybe even astigmatism) which lead to people slouching and curving their back forward. The continued action over time eventually makes most people decrease in height from bad lifestyle. The ironic thing is that the people who can get the most dramatic and most noticeable results are the ones who actually have lived lazy, unhealthy lives. They are the ones who have lost the most height from bad lifestyle choices. They minimized the height potential. For the people who have been exercising and performed in athletics, they are the ones who will probably get the least results since they have already pushed their bodies to the limit of what their body is capable of.
I would say that in terms of what is realistically possible, if the desired height increase was to only 1 inch, the percentage of the population who can achieve that could be around 30%. For 2 inches, the percentage is around 2-3 percent.