rates of different years

[FAN.WEN]

Dear instructors,

When we are dealing with comparison sentences focusing on rates of different years (e.g. interest rates, inflation rates, growth rates, etc.) , should we assume they are actually same but fluctuating in different years or different individual rates?

For example,

The interest rate of this year is as high as the interest of last year.
The interest rate of this year is as high as that of last year.
The interest rate of this year is as high as it was last year.

Can you please indicate which one is correct in the above example? Is it a definite rule to eliminate wrong answers?

Thanks.

[RonPurewal]

hello,
presuming this question is based on an actual GMAT item—please cite the problem that originally inspired this question (including a citation of the original source, as per the forum rules).

thank you.