diff --git a/includes/admin/reports/class-wc-admin-report.php b/includes/admin/reports/class-wc-admin-report.php
index 2e101f1c627..ae5e19bb51d 100644
--- a/includes/admin/reports/class-wc-admin-report.php
+++ b/includes/admin/reports/class-wc-admin-report.php
@@ -17,6 +17,10 @@ if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly
  */
 class WC_Admin_Report {
 
+	public $chart_interval;
+	public $group_by_query;
+	public $barwidth;
+	public $chart_groupby;
 	public $start_date;
 	public $end_date;
 
diff --git a/includes/admin/reports/class-wc-report-coupon-usage.php b/includes/admin/reports/class-wc-report-coupon-usage.php
index dfc9eb2100d..05448a75fd7 100644
--- a/includes/admin/reports/class-wc-report-coupon-usage.php
+++ b/includes/admin/reports/class-wc-report-coupon-usage.php
@@ -4,6 +4,7 @@
  */
 class WC_Report_Coupon_Usage extends WC_Admin_Report {
 
+	public $chart_colours = array();
 	public $coupon_codes = array();
 
 	/**
diff --git a/includes/admin/reports/class-wc-report-customers.php b/includes/admin/reports/class-wc-report-customers.php
index 4bd4f6b701c..34853533e78 100644
--- a/includes/admin/reports/class-wc-report-customers.php
+++ b/includes/admin/reports/class-wc-report-customers.php
@@ -4,6 +4,8 @@
  */
 class WC_Report_Customers extends WC_Admin_Report {
 
+	public $chart_colours = array();
+	
 	/**
 	 * Get the legend for the main chart sidebar
 	 * @return array
diff --git a/includes/admin/reports/class-wc-report-sales-by-category.php b/includes/admin/reports/class-wc-report-sales-by-category.php
index dd19ab1a47e..3ea0067bf61 100644
--- a/includes/admin/reports/class-wc-report-sales-by-category.php
+++ b/includes/admin/reports/class-wc-report-sales-by-category.php
@@ -4,6 +4,7 @@
  */
 class WC_Report_Sales_By_Category extends WC_Admin_Report {
 
+	public $chart_colours = array();
 	public $show_categories = array();
 
 	/**
diff --git a/includes/admin/reports/class-wc-report-sales-by-date.php b/includes/admin/reports/class-wc-report-sales-by-date.php
index d5556548d0b..25deb455dc4 100644
--- a/includes/admin/reports/class-wc-report-sales-by-date.php
+++ b/includes/admin/reports/class-wc-report-sales-by-date.php
@@ -4,6 +4,8 @@
  */
 class WC_Report_Sales_By_Date extends WC_Admin_Report {
 
+	public $chart_colours = array();
+	
 	/**
 	 * Get the legend for the main chart sidebar
 	 * @return array
diff --git a/includes/admin/reports/class-wc-report-sales-by-product.php b/includes/admin/reports/class-wc-report-sales-by-product.php
index 5f4635ddeb1..95a5cf91adf 100644
--- a/includes/admin/reports/class-wc-report-sales-by-product.php
+++ b/includes/admin/reports/class-wc-report-sales-by-product.php
@@ -4,6 +4,7 @@
  */
 class WC_Report_Sales_By_Product extends WC_Admin_Report {
 
+	public $chart_colours = array();
 	public $product_ids = array();
 
 	/**