Statistics only display data for the selected region

app/controllers/stats_controller.rb

@@ -20,7 +20,10 @@ class StatsController < ApplicationController
   end
 
   def local
-    @regions = @events.joins(:region).group(:region_id, year_grouping).count
+    @region_events = @events.group(:region_id, year_grouping).count
+    @regions = Region.all.find_all do |region|
+      @years.sum { |year| @region_events[[region.id, year[0]]] || 0 } > 0
+    end
     @city_events = @events.group(:city).having('count(city) > 3')
                           .order('count(city) desc').count
   end

app/views/stats/index.html.haml

@@ -61,15 +61,15 @@
       %th= t '.total'
       %th/
   %tbody
-    - Region.all.each do |region|
+    - @regions.each do |region|
       %tr
         %th.region= region
         - total = 0
         - @years.each do |year|
           %td.quantity
-            - total += @regions[[region.id, year[0]]] || 0
+            - total += @region_events[[region.id, year[0]]] || 0
             = link_to root_path(year: year[0].to_s, region: region.id) do
-              = number_with_delimiter @regions[[region.id, year[0]]]
+              = number_with_delimiter @region_events[[region.id, year[0]]]
         %th.quantity.total= number_with_delimiter total
         %td.sparkline/