User-agent: *
Crawl-delay: 30
User-agent: Googlebot 
 Disallow: /wp-content/files/2011/06/pdf/
 Disallow: /wp-content/files/2017/04/golf/pdf/
 Disallow: /wp-content/files/2011/10/pdf/
 Disallow: /wp-content/files/2013/12/pdf/
 Disallow: /wp-content/files/2014/04/pdf/

Disallow: *.pdf$  # Block pdf files. Non-standard but works for major search engines.
Disallow: *.doc$  # Block word files. Non-standard but works for major search engines.
Disallow: *.docx$  # Block word files. Non-standard but works for major search engines.