[Grammar] in the last year/for the last year

[Kotfor]

When we use "in the last year" being at the present it means 365 days backward.

What does it mean in the past and what's the difference with "for the last year"?

1) The plant was closed on the 15 of January in 1987; I was there for the last year.
2) The plant was closed on the 15 of January in 1987; I was there in the last year.

1) I was there from the first of January 1987 till the 15 of January in 1987
2) I was there from the 15 of January 1986 till the 15 of January in 1987

Is it correct?

 

[5jj]

1) The plant was closed on 15 January 1987; I was there for the last year.
I was there from 16 January 1986 till 15 January 1987

2) The plant was closed on the 15 of January in 1987; I was there in the last year.
I was there at some time between 16 January 1986 and 15 January 1987, possibly for the whole year.

 

[Kotfor]

How shall I say if I need to point out that I was there only within the last CALENDAR year which is only from the first of January 1987 till the 15 of January in 1987

 

[5jj]

How shall I say if I need to point out that I was there only within the last CALENDAR year which is only from the first of January 1987 till the 15 of January in 1987

I was there for the final two weeks.