You don't even have to be close, sometimes.

I earned BiB PLT in 2013 for 2014.

In 2014, I got to 75 nights by way of BiB, rollover, and the credit card, so PLT for 2015.

In 2015, I had 18 nights total, made up of 15 from the credit card, 1 for the credit card free night, and 2 nights on an award stay. So no paid nights at all. And they still extended me PLT for the 2016 year.