Questions regarding 485 filing, please help me!

I have two questions regarding I-485 application:

1. They request W-2 forms and tax return forms for past three years, but I was just employed for 1 year and only one W-2 form and one year tax return are available. Should I attach a statement to explain this?

2. I was employed in the middle of a year, so the W-2 form does not reflect my real annual income. Should I also attach a statement to explain it?

Thanks in advance for all your time and help.