$last = preg_replace('/[^0-9.]/', '', $last); // 数字と小数点部分だけ抽出ネタ元 http://nkawamura.hatenablog.com/entry/2013/06/15/143729

=COUNTIF(A1:A10,">0")/COUNT(A1:A10)ネタ元 http://detail.chiebukuro.yahoo.co.jp/qa/question_detail/q1034679975