Complex sentence: According to the Polish census of 1931 the Nowogródek Voivodeship was home to about 616,000 ethnic Belorussians, or ~ 39% of the total population of the province, exceeding the number of ethnic Poles by eight percentage points.
Split into simpler sentences: According to the Polish census of 1931 the Nowogródek Voivodeship was home to about 616,000 ethnic Belorussians, or ~ 39% of the total population of the province. The number of ethnic Belorussians exceeded the number of ethnic Poles by eight percentage points.