percentage of those who respond to Herceptin

I dont know the percentages of who respond and i am a metastatic girl but i have just passed 9 years on herceptin and have not had chemo since my 7 rounds of taxetere, xeloda and herceptin back in 2002.. SO i am very thankful for herceptin and i live my life around my 3 weekly trip to hospital and think of all the many things i have been able to do in the last 9 years.....where there is hope the is life..