diff --git a/app/controllers/statistics_controller.rb b/app/controllers/statistics_controller.rb
index db014338..0c4a373a 100644
--- a/app/controllers/statistics_controller.rb
+++ b/app/controllers/statistics_controller.rb
@@ -37,7 +37,7 @@ class StatisticsController < ApplicationController
     respond_to do |format|
       format.html { render 'rfc_activity_history' }
       format.json do
-        interval = params[:interval].to_s.nil? ? 'year' : params[:interval]
+        interval = params[:interval].to_s.empty? ? 'year' : params[:interval]
         from = DateTime.strptime(params[:from], '%Y-%m-%d') rescue DateTime.new(0)
         to = DateTime.strptime(params[:to], '%Y-%m-%d') rescue DateTime.now
         render(json: ranged_rfc_data(interval, from, to))