B train announcements graded 'F'

Say what?!?

That's what riders on the B train may be saying, according to the Straphangers Campaign, since the line was rated the worst performing in an annual survey on subway announcements.

Overall, in 2010, 83 percent of all subway announcements are clear and accurate, about the same as in 2009.

Here's a look at the subway lines with the highest percentage of clear and accurate announcements and those with the lowest: