Each year approximately 30,000 properties are added to the National Register as part of districts or by individual listings .
Each year around 30,000 properties are added to the National Register as part of districts or through individual listings .
Each year around 30,000 properties are added to the National Register as part of districts or through individual listings .
اجعل هذا النص أقل تعقيدًا: Each year approximately 30,000 properties are added to the National Register as part of districts or by individual listings . خرج: