Ok, I made some research and testing. Using Transformable type, solution is simple:
1. What do I declare inside my NSManagedObject class?
@NSManaged var values: [NSNumber] //[Double] also works
2. What do I declare inside my .xcdatamodel?
Transformable
data type.
3. How do I save this in my Entity?
statistics!.values = [23, 45, 567.8, 123, 0, 0] //just this
“You can store an NSArray or an NSDictionary as a transformable attribute. This will use the NSCoding to serialize the array or dictionary to an NSData attribute (and appropriately deserialize it upon access)” – Source
Or If you want to declare it as Binary Data then read this simple article: