""Most notably, the percentage of money spent on transportation almost tripled: it was 5% in 2009, and by 2011, it had reached 14%."

[hardyweineberg]

A. "Most notably, the percentage of money spent on transportation almost tripled: it was 5% in 2009, and by 2011, it had reached 14%."
B. "Most notably, the percentage of money spent on transportation almost tripled; it was 5% in 2009, and by 2011, it had reached 14%."

I read somewhere that colons and semicolons can never be used interchangeably. However, I feel that either a colon or a semicolon can be used in this sentence; that is, it would be grammatical to use any.

 

[jutfrank]

This is part of your response to an IELTS task, isn't it? Both punctuation marks work fine here. That is, an examiner would be satisfied that you have good control of punctuation.

 

[hardyweineberg]

This is part of your response to an IELTS task, isn't it?

Yes, it is.