How many satellites were orbiting the Earth as of 2017?

According to the Index of Objects Launched into Outer Space maintained by the United Nations Office for Outer Space Affairs (UNOOSA), there are 4,635 satellites currently orbiting the planet as of 2017, an increase of 8.91% over 2016.

This increase is fuelled by small satellites and cubesats (which are miniaturized satellites). New technology has significantly reduced the cost to design, build and launch these, and this has been accompanied with an increase in commercial providers becoming involved in the market. A report issued earlier by the Satellite Applications Catapult predicted that 1,300 of these satellites will be launched over the next three years. If one consider that just under 7,900 objects have been launched into space, this would equate to 16.5% of the total launches over the last 60 years!