demolished during the 20th century
... that one in six of all English country houses are thought to have been demolished during the 20th century?
... that one in six of all <a href="./English_country_house" id="mwC9M" rel="mw:WikiLink" title="English country house">English country houses</a> <i id="mwC9Q">(<a href="./Tong_Castle" id="mwC9U" rel="mw:WikiLink" title="Tong Castle">Tong Castle</a> pictured)</i> are thought to have been <b id="mwC9Y"><a href="./Destruction_of_country_houses_in_20th-century_Britain" id="mwC9c" rel="mw:WikiLink" title="Destruction of country houses in 20th-century Britain">demolished during the 20th century</a></b>?