Previous sales if years are in Random

[pavansonu99]

Hi

I have date like this

Year        custmorID       sales

2000          101               200

2000          102               150

2000          103               300  

2002          109               220

2002          101               250

2005          101                350

2005          102                230

2007          104               240

2007          109               500

2011          102               150

2011          103               250

2011          109               150

2012          101                350

2012          102                230

2012          104               240

2016          101               200

2016          102               400

2016          109               700

i want sales of present year and previous year   ( if i click on 2016 i want to get sales of 2016 and 2012 and if i click on 2012 i want to get sales of 2012 and 2011) i my data years are in random..

please share your Ans

thanks in advance