diff --git a/openapi.yaml b/openapi.yaml
index afe6415..627d7b4 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -2102,6 +2102,55 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/SimpleStatusResponse'
+  /statistics/{taskgroupID}/{startingDate}/{endingDate}:
+    get:
+      security:
+        - API_TOKEN: []
+      tags:
+        - history
+      parameters:
+        - name: taskgroupID
+          in: path
+          description: internal id of taskgroup
+          required: true
+          schema:
+            type: number
+            example: 1
+        - name: startingDate
+          in: path
+          description: starting date
+          required: true
+          schema:
+            type: string
+            format: date
+        - name: endingDate
+          in: path
+          description: starting date
+          required: true
+          schema:
+            type: string
+            format: date
+      responses:
+        200:
+          description: Operation successfull
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: '#/components/schemas/TaskgroupActivityInfo'
+        403:
+          description: No permission
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/SimpleStatusResponse'
+        404:
+          description: Schedule not found
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/SimpleStatusResponse'
   /history/schedules/{date}:
     get:
       security: