Supers are classified by power level in by the various governments and organisations that exist in the world of 2198. These correspond to might ratings of 2-6 in the dots of the Larger Than Life system.
In ascending order of power:
Gammas (2dot)
The most common power level of supers, the population of gamma level supers is something in the region of two million. Though they are generally well more than a match for an individual norm a group with the right equipment can generally still overcome then. Many gammas try to ignore their powers and lead relatively normal lives.
Deltas (3dot)
There are a little under a hundred thousand deltas in the Earth's population and almost all of them work for organisations designed to turn the talents of supers to their best and most productive use, very few deltas still attempt to still lead normal lives. They tend not to be powerful enough to survive on their own, as they would often be targeted by supervillians for their own nefarious purposes. A group of ords, regardless of equipment and training would find it very difficult indeed to take down a delta.
Betas (4dot)
The betas number several thousand. Again they tend not to stay independent, but rarely don't have a say in where they end up as it can be quite difficult to coerce them against their will. There have been plenty of famous Betas, who through hard work or inventive methods have made a real difference to the world as a whole.
Alphas (5dot)
There are a few hundred alphas, and almost all of them have risen to positions of prominence or influence. Most famous supers are Alpha level and several prominent organisations and super teams are lead by alphas. Ords have a life span generally measured in seconds in the face of a hostile alpha, a small team of Betas or a large group of Deltas have been known to have success against alpha villains.
Omegas (6dot)
There are less than 2 dozen Omegas on earth. And all of them are well known, even the ones that attempt to keep a low profile. A large team of well coordinated Alphas and Betas have gone up against Omegas successfully in the past, but since there is no known upper limit to the power of an Omega it is feared that one might eventually arise that would require a team of other Omegas to stop.