"Increasing by 300 a year it will be a rare disease for another 140 years."

As more people become infected, more people will be at risk, so the rate of increase will also increase.

You will not see a steady 300 per year, but a similar percentage each year, itself increasing slightly as the pool of vulnerable young girls gets having unprotected sexgets proportionately smaller.

10% of young women have chlamydia.

thats around 300,000.

around the same number as think you can't get pregnant standing up.

And I would argue, probably the same number of women that could eventually be infected with HIV if nothing is done to change young peoples habits.