I don't really get the OP, or more precisely, I think the OP got his statistics wrong.
Nobility around 1% of the population is a lowest estimation or, maybe, representating the "aristocratic" or titled (as title and nobility aren't synonymous) part of european nobility, unless we're talking of periods posterior to Middle-Ages where nobility tended to be more restrictive of course (actually, it may be that, as I don't see how you could have precise statistics with medieval data).
The border between noble and non-noble was often socially blurry : and a poor knight couldn't always be differenciated from non-nobles.
While ten percent of the population wasn't reached everywhere (but was elsewhere than Poland, in Spain by exemple), if you really need a stat (to be taken really cautiously), nobility could represent something between 2 and 5% of the population depending the aeras in most regions, and up to 10% or less than 1% in some other.
By exemple, medieval France had, depending on the regions, around 4% (probably more, as censies didn't really existed per se) of nobles on its population, while England had less then 0,5%, and Spain had around 10% before the core of XIV century crisis (the rates being possibly, but speculativly, higher before that, and certainly lower afterwards).
Finally, Polish nobility (while it seems to have concerned 8% of the population before the disapperence of the kingdom) wasn't that much distinct in this regard for the era, but didn't was targeted or as much, by both the reinforcement of royal powers and, by the other hand, the demographic crisis that decimated western nobility (that went distinct from gentry, at the difference of polish one).
Generally, some features increased the "proportion" : being on a "hot" border (Reconquista Spain, Hungary, Latin States), higher population (towns, medieval nothern France).
It may be helpful to increase ATL nobility in some regions, but not enough for the whole medieval culture.
Now, in order to have more "nobles", we must enlarge its definition.
With the famous statements "Nul seigneur sans terre" (No lord without land) in Northern France, "nul seigneur sans titre" (No lord without title) in southern France or "Nul titre sans terre" (No title without land) in part of western France.
As you see, even within a same kingdom, the definition was far from being the same.
Eventually, the ideal outcome would be to have freemen of early middle ages being divided between nobles (that would have been a synonymous for free and -relativly- powerful) and other layers of peasantry.
It's doable, but would require an harsher post-carolingian Europe, with more infighting and a even more harsh feudal structuration of the territory (with aristocracy being more prone to take on "free" pesantry, as much they did for allods by exemple).
It would have required more ressources, and more men that they could have "obtained" the same way than knighthood was created : from the peasantry.
No "Peace of God" movement, or its failure, could help.