         static let birthDate = "birthDate"
         static let heightInMeters = "heightInMeters"
         static let sexInBoolean = "sexInBoolean"
-        static let bloodPressureMeasurements = "bloodPressureMeasurements"
+        static let bloodPressureMeasurementsSorted = "bloodPressureMeasurementsSorted"
     }
     
     // Create a new patient

            case .female: self.sexInBoolean = false
        }
        
        self.bloodPressureMeasurements = bloodPressureMeasurements
    }
    
    // Encoder used to store a patient.

        encoder.encode(birthDate, forKey: PropertyKey.birthDate)
        encoder.encode(heightInMeters, forKey: PropertyKey.heightInMeters)
        encoder.encode(sexInBoolean, forKey: PropertyKey.sexInBoolean)
        encoder.encode(bloodPressureMeasurementsSorted, forKey: PropertyKey.bloodPressureMeasurementsSorted)
    }
    
    public required convenience init?(coder decoder: NSCoder) {
