Poland's nobility were also more numerous than those of all other European countries, constituting some 10–12% of the total population of historic Polish–Lithuanian Commonwealth also some 10–12% among ethnic Poles on ethnic Polish lands (part of Commonwealth), but up to 25% of all Poles worldwide (szlachta could dispose more of resources to travels and/or conquering), while in some poorer regions (e.g., Mazowsze, the area centred on Warsaw) nearly 30%. However, according to  szlachta comprised around 8% of the total population in 1791 (up from 6.6% in the 16th century), and no more than 16% of the Roman Catholic (mostly ethnically Polish) population. It should be noted, though, that Polish szlachta usually incorporated most local nobility from the areas that were absorbed by Poland–Lithuania (Ruthenian boyars, Livonian nobles, etc.) By contrast, the nobilities of other European countries, except for Spain, amounted to a mere 1–3%, however the era of sovereign rules of Polish nobility ended earlier than in other countries (excluding France) yet in 1795 (see: Partitions of Poland), since then their legitimation and future fate depended on legislature and procedures of Russian Empire, Kingdom of Prussia or Habsburg Monarchy. Gradually their privileges were under further limitations to be completely dissolved by March Constitution of Poland in 1921.
Polish szlachta usually incorporated who?
most local nobility from the areas that were absorbed by Poland–Lithuania