The numbers for the year 2011 won't be available until sometime in 2012.
There are approximately 650 to 700 reported sightings each year world-wide.
Officially, UFO reported sightings are not available until early in the new year. So 2011 sightings won't be published until 2012.
For the year 2009 the total sightings were 643. Of these some may have been found to be explainable but some can't easily be explained away.
There are hundreds every year around the world.
I believe there was a sighting in Jan. of 2012. Below is a link to the most recent UFO sightings.
Of the 600+ sightings reported every year, many of those are from America. The most well known is of course the 1947 crash sight in Rosewell, NM.
45
five
There is no such thing as a mermaid.
An average of about 650 per year are reported, so multiply that by 5 and there's your answer.
So few sightings are actually reported, there are no reliable statistics.
MUFON usually doesn't have the total sightings for the previous year until about June (2013).