"Most wizards these days are half-blood anyway. If we hadn't married Muggles we'd've died out."
Half-blood was the term commonly given to wizards and witches who had known muggle or muggle-born parents or grandparents. By the 1900s, half-bloods were the most common type of magicalperson, as the pure-blood wizarding population would've become extinct had they not intermarried with muggles and muggle-borns.