Here is the requirement, you need to have 3 years tax return papers which is mentioned below. if you are planning to apply for 2018, then you have to provide 2017,2016,2015 tax returns once you get 2017 returns. otherwise you have to show 2016,2015,2014 tax return papers
Federal Income Table for Parents and Grandparents Sponsorship (2016, 2015, 2014)
Size of Family Unit Minimum Income
2016 Minimum Income
2015 Minimum Income
2014
2 persons $39,371 $38,618 $38,272
3 persons $48,404 $47,476 $47,051
4 persons $58,768 $57,642 $57,125
5 persons $66,654 $65,377 $64,791
6 persons $75,174 $73,733 $73,072
7 persons $83,695 $82,091 $81,355
If more than 7 persons, for each additional person, add $8,522 $8,358 $8,271
The Minimum Necessary Income requirement, which you must meet for each of the three years preceding the date of your application, is equal to the Low Income Cut-Offs (LICO) plus 30%.
Note: If you are applying in 2017, you must provide proof of income from the Canada Revenue Agency (CRA) for the taxation years of 2016, 2015 and 2014.