Transplanted hair is not falling out or growing? I had my hair transplant in September 2012 (almost 1 yr 8 months).

I had my hair transplant in September 2012 (almost 1 yr 8 months). 2000 grafts it was for front line and to crown area. 60% off them shredded after transplant and start growing. but 40% of my hair have not fallen out and they are not even growing. I can feel all the transplanted hair with the same length of 2 mm(same as the day of transplantation).Could you let me know what may be the possible reason that my transplanted hair neither fallen out nor growing even after such a long time.