2010

2011

2012

2013

Avrg.

January

6.289

6.61

6.964

6.591

6.613

February

6.403

7.07

6.847

7.136

6.864

March

6.129

6.996

7.116

6.302

6.635

April

6.076

6.491

5.764

6.024

6.088

May

6.18

6.229

6.092

6.498

6.249

June

5.84

5.943

5.906

5.631

5.83

July

5.52

6.052

5.464

5.489

5.905

August

5.78

6.054

5.8966

5.889

5.905

September

6.67

6.386

6.686

6.674

6.604

October

6.402

5.937

6.29

6.475

6.276

November

5.681

5.58

5.788

5.31

5.589

December

6.33

6.148

5.751

5.657

5.971