diff --git a/AIParkingApplication/Statistic.cs b/AIParkingApplication/Statistic.cs
index 493b0ba..1b58d7b 100644
--- a/AIParkingApplication/Statistic.cs
+++ b/AIParkingApplication/Statistic.cs
@@ -58,10 +58,18 @@ namespace AIParkingApplication
                 }));
                 lblVehicleTotalIn.Invoke(new Action(() =>
                 {
+                    if (string.IsNullOrEmpty(parkInfo.TotalIn))
+                    {
+                        parkInfo.TotalIn = "0";
+                    }
                     lblVehicleTotalIn.Text = parkInfo.TotalIn;
                 }));
                 lblVehicleTotalOut.Invoke(new Action(() =>
                 {
+                    if (string.IsNullOrEmpty(parkInfo.TotalOut))
+                    {
+                        parkInfo.TotalOut = "0";
+                    }
                     lblVehicleTotalOut.Text = parkInfo.TotalOut;
                 }));