Frequent Switchs

I am just 1.5 years old into my current company and the growth seems to be slow here.Hence wondering if I can look outside in the market for some new opportunities.

Just an anxiety: What should I answer if the HR asks me about the frequent switches?

I always get stuck on this question ( ofcourse I do it for quick growth) but how can I sugarcoat to justify this?

Please comment and share your thoughts.