feat: added sample data

data/sample_data.csv

@@ -0,0 +1,6 @@
+Year,Sales,Employee expense,Net profit,EBITDA,EBIT,RoCE,interest,WC %
+2020,1000,200,100,300,250,10,50,5
+2021,1200,220,150,350,300,12,55,6
+2022,1400,250,200,400,350,15,60,7
+2023,1600,270,250,450,400,18,65,8
+2024,1800,300,300,500,450,20,70,9

data_processor.py

@@ -9,7 +9,8 @@ class DataProcessor:
         if data_path and os.path.exists(data_path):
             self.data_path = data_path
         else:
-            self.data_path = os.path.join(os.path.dirname(os.path.dirname(__file__)), 'data', 'sample_data.xlsx')
+            # Use the new sample_data.csv with all required columns
+            self.data_path = os.path.join(os.path.dirname(os.path.dirname(__file__)), 'data', 'sample_data.csv')
         self.data = self.load_data(self.data_path)
 
     def load_data(self, path):