How to concatenate symbol in json rails 4

I need to add '%' symbol in 'votes_count' field

My controller,

@celebrity = Celebrity.includes(:category).order(votes_count: :desc)

I am counting the total votes here

  total_votes = Vote.count.to_f

changing the total no. of votes to percentage

  @celebrity.each do |celeb|       
    celeb["votes_count"] = (celeb.votes_count / total_votes * 100).round(2)
  end

here, I am changing into json

respond_to do |format|      
  format.json { render json: @celebrity.to_json(:include =>{:category => {:only => [:category]}})}      
end

My output is [{"id":3,"name":"saravana","gender":false,"category_id":"1","votes_count":25}]

My question is how can I add '%' symbol in votes_count