Confirmed eruptions 2015

An average 42 confirmed volcanic eruptions were registered in 2015

42 confirmed volcanic eruptions were registered in 2015 which is just one more than the 2014 total of 41.
Only five eruptions in 2015 were strong enough to register on the Max VEI Index with the biggest being the Raung Java volcano in Indonesia which registered a 3.
In contrast 2014 registered 30 confirmed eruptions on the Max VEI Index with the strongest being a category 4, coincidentally at the Kelut volcano, Java, Indonesia also on Feb 13th!

Click on graph to enlarge.
Are confirmed volcano eruptions increasing?
Well not in the last 15 years as the graph clearly shows.
The largest eruption of the on the Volcanic Explosivity Index, ( VEI) in the last 15 years was a 5 on June the 4th 2011 at the Puyehue-Cordon Caulle in Chile and Argentina.
All data from The Smithsonian Institution
The Mount Tambora (1815 eruption) was a 7 on the Volcanic Explosivity Index, ( VEI), responsible for 92,000 deaths, is the largest and deadliest volcanic eruption in recorded history.
It was so large it caused the "Year Without a Summer" in 1816,  see here and here.
In 1833 the  Krakatoa eruption killed 36,417, and scored a 6 on the Volcanic Explosivity Index, ( VEI) and was heard 3,000 miles (4,800 km) away.
It caused a 5 year volcanic winter.
The island had three volcanoes.
Perboewatan (410 ft) and Danan (1,480 ft) was destroyed during the eruption while Rakata (2,667 ft) was only half destroyed but it still remains above sea level.
In 1928, a new volcano called Anak Krakatoa (1,063 ft) grew above sea level, forming a new island by Rakata's island. 
The largest eruption in the 20th century was the Novarupta volcano in 1912

A total of 41 volcano eruptions where confirmed in the year 2014, which you can see on the wonderful graph below which falls into an average figure for the last 60 years or so.
The largest eruption of the year was the Kelut Volcano in Java, Indonesia measuring 4 on the Volcanic Explosivity Index, ( VEI).

The graph above showing all eruptions and strength history since 1600 with a max VEI.

Below is a graph showing eruption and strength history since 1600 showing a more realistic VEI to 4.

Thanks to Morpheus for the 2 wonderful graphs above