1985 database

1995 database

2005 database

2015 database

Mean

2307.57

4507.42

5226.74

5019.21

Standard deviation

1186.04

2619.29

2557.09

1797.37

10th percentile

1220.83

2023.82

2598.57

2854.18

50th percentile

2072.26

4117.99

4869.93

4839.32

90th percentile

3627.10

7188.94

8004.57

7182.37