Solve the following sql problem:
What is the average actual profit by 1937 Lincoln Berline?

Schema:
SCHEMA:
- Table: offices
  - Column: officeCode
    - Samples: [1, 2, 3, 4, 5]
  - Column: city
    - Samples: [San Francisco, Boston, NYC, Paris, Tokyo]
  - Column: phone
    - Samples: [+1 650 219 4782, +1 215 837 0825, +1 212 555 3000, +33 14 723 4404, +81 33 224 5000]
  - Column: addressLine1
    - Samples: [100 Market Street, 1550 Court Place, 523 East 53rd Street, 43 Rue Jouffroy D'abbans, 4-1 Kioicho]
  - Column: addressLine2
    - Samples: [Suite 300, Suite 102, apt. 5A, None, None]
  - Column: state
    - Samples: [CA, MA, NY, None, Chiyoda-Ku]
  - Column: country
    - Samples: [USA, USA, USA, France, Japan]
  - Column: postalCode
    - Samples: [94080, 02107, 10022, 75017, 102-8578]
  - Column: territory
    - Samples: [NA, NA, NA, EMEA, Japan]
- Table: employees
  - Column: employeeNumber
    - Samples: [1002, 1056, 1076, 1088, 1102]
  - Column: lastName
    - Samples: [Murphy, Patterson, Firrelli, Patterson, Bondur]
  - Column: firstName
    - Samples: [Diane, Mary, Jeff, William, Gerard]
  - Column: extension
    - Samples: [x5800, x4611, x9273, x4871, x5408]
  - Column: email
    - Samples: [dmurphy@classicmodelcars.com, mpatterso@classicmodelcars.com, jfirrelli@classicmodelcars.com, wpatterson@classicmodelcars.com, gbondur@classicmodelcars.com]
  - Column: officeCode
    - Samples: [1, 1, 1, 6, 4]
  - Column: reportsTo
    - Samples: [None, 1002, 1002, 1056, 1056]
  - Column: jobTitle
    - Samples: [President, VP Sales, VP Marketing, Sales Manager (APAC), Sale Manager (EMEA)]
- Table: customers
  - Column: customerNumber
    - Samples: [103, 112, 114, 119, 121]
  - Column: customerName
    - Samples: [Atelier graphique, Signal Gift Stores, Australian Collectors, Co., La Rochelle Gifts, Baane Mini Imports]
  - Column: contactLastName
    - Samples: [Schmitt, King, Ferguson, Labrune, Bergulfsen]
  - Column: contactFirstName
    - Samples: [Carine , Jean, Peter, Janine , Jonas ]
  - Column: phone
    - Samples: [40.32.2555, 7025551838, 03 9520 4555, 40.67.8555, 07-98 9555]
  - Column: addressLine1
    - Samples: [54, rue Royale, 8489 Strong St., 636 St Kilda Road, 67, rue des Cinquante Otages, Erling Skakkes gate 78]
  - Column: addressLine2
    - Samples: [None, None, Level 3, None, None]
  - Column: city
    - Samples: [Nantes, Las Vegas, Melbourne, Nantes, Stavern]
  - Column: state
    - Samples: [None, NV, Victoria, None, None]
  - Column: postalCode
    - Samples: [44000, 83030, 3004, 44000, 4110]
  - Column: country
    - Samples: [France, USA, Australia, France, Norway]
  - Column: salesRepEmployeeNumber
    - Samples: [1370, 1166, 1611, 1370, 1504]
  - Column: creditLimit
    - Samples: [21000.0, 71800.0, 117300.0, 118200.0, 81700.0]
- Table: orders
  - Column: orderNumber
    - Samples: [10100, 10101, 10102, 10103, 10104]
  - Column: orderDate
    - Samples: [2003-01-06, 2003-01-09, 2003-01-10, 2003-01-29, 2003-01-31]
  - Column: requiredDate
    - Samples: [2003-01-13, 2003-01-18, 2003-01-18, 2003-02-07, 2003-02-09]
  - Column: shippedDate
    - Samples: [2003-01-10, 2003-01-11, 2003-01-14, 2003-02-02, 2003-02-01]
  - Column: status
    - Samples: [Shipped, Shipped, Shipped, Shipped, Shipped]
  - Column: comments
    - Samples: [None, Check on availability., None, None, None]
  - Column: customerNumber
    - Samples: [363, 128, 181, 121, 141]
- Table: payments
  - Column: customerNumber
    - Samples: [103, 103, 103, 112, 112]
  - Column: checkNumber
    - Samples: [HQ336336, JM555205, OM314933, BO864823, HQ55022]
  - Column: paymentDate
    - Samples: [2004-10-19, 2003-06-05, 2004-12-18, 2004-12-17, 2003-06-06]
  - Column: amount
    - Samples: [6066.78, 14571.44, 1676.14, 14191.12, 32641.98]
- Table: productlines
  - Column: productLine
    - Samples: [Classic Cars, Motorcycles, Planes, Ships, Trains]
  - Column: textDescription
    - Samples: [Attention car enthusiasts: Make your wildest car ownership dreams come..., Our motorcycles are state of the art replicas of classic as well as co..., Unique, diecast airplane and helicopter replicas suitable for collecti..., The perfect holiday or anniversary gift for executives, clients, frien..., Model trains are a rewarding hobby for enthusiasts of all ages. Whethe... (truncated)]
  - Column: htmlDescription
    - Samples: [None, None, None, None, None]
  - Column: image
    - Samples: [None, None, None, None, None]
- Table: products
  - Column: productCode
    - Samples: [S10_1678, S10_1949, S10_2016, S10_4698, S10_4757]
  - Column: productName
    - Samples: [1969 Harley Davidson Ultimate Chopper, 1952 Alpine Renault 1300, 1996 Moto Guzzi 1100i, 2003 Harley-Davidson Eagle Drag Bike, 1972 Alfa Romeo GTA]
  - Column: productLine
    - Samples: [Motorcycles, Classic Cars, Motorcycles, Motorcycles, Classic Cars]
  - Column: productScale
    - Samples: [1:10, 1:10, 1:10, 1:10, 1:10]
  - Column: productVendor
    - Samples: [Min Lin Diecast, Classic Metal Creations, Highway 66 Mini Classics, Red Start Diecast, Motor City Art Classics]
  - Column: productDescription
    - Samples: [This replica features working kickstand, front suspension, gear-shift ..., Turnable front wheels; steering function; detailed interior; detailed ..., Official Moto Guzzi logos and insignias, saddle bags located on side o..., Model features, official Harley Davidson logos and insignias, detachab..., Features include: Turnable front wheels; steering function; detailed i... (truncated)]
  - Column: quantityInStock
    - Samples: [7933, 7305, 6625, 5582, 3252]
  - Column: buyPrice
    - Samples: [48.81, 98.58, 68.99, 91.02, 85.68]
  - Column: MSRP
    - Samples: [95.7, 214.3, 118.94, 193.66, 136.0]
- Table: orderdetails
  - Column: orderNumber
    - Samples: [10100, 10100, 10100, 10100, 10101]
  - Column: productCode
    - Samples: [S18_1749, S18_2248, S18_4409, S24_3969, S18_2325]
  - Column: quantityOrdered
    - Samples: [30, 50, 22, 49, 25]
  - Column: priceEach
    - Samples: [136.0, 55.09, 75.46, 35.29, 108.06]
  - Column: orderLineNumber
    - Samples: [3, 2, 4, 1, 4]

SELECT SUM(T1.priceEach - T2.buyPrice) / COUNT(*) FROM orderdetails AS T1 INNER JOIN products AS T2 ON T1.productCode = T2.productCode WHERE T2.productName = '1937 Lincoln Berline'