Cust_id  Year  Revnue
1        2016  679862
1        2017  705365
1        2018  195662
1        2019  201234
2        2016  51074
2        2017  50611
2        2018  19070
2        2019  20123

Cust_id  Year  Revnue
1        2018  779862
1        2019  125662
2        2017  23456
2        2018  32856
2        2019  26602

Cust_id  Year  Revnue projections
1        2016  679862  null
1        2017  705365  null
1        2018  195662  779862
1        2019  201234  125662
2        2016  51074   null
2        2017  50611   23456
2        2018  19070   32856
2        2019  20123   26602