Almost is really close to all companies.
Check it out:

Since the FDA released its Guidance for Industry #213 in December 2013, all but one affected company have committed in writing to comply with the voluntary guidance. And the committed companies market over 99 percent of the drugs affected by the guidance FDA announced this week. Guidance 213 directs companies to seek withdrawal of approvals for production use of antimicrobial drugs determined to be important in human medicine. In a March 26 release, FDA says it is encouraged by the strong response thus far and will continue to monitor ongoing participation and provide public updates on a periodic basis.