Purpose of Swapping

0

/

1987

2

/

1977

0

/

1977

4.5

/

1978

2

/

1978

2

/

1978

2

/

1978

0

/

1978

2

/

1978

4.2

/

2014

5

/

2023

2

/

1978

3.3

/

2017

5.7

/

2017

0

/

1986

2

/

1977

7

/

2006

6

/

2009

1.5

/

2013

4

/

2019