Number of significant volcanic eruptions

The Significant Volcanic Eruption Database is a global listing of over 500 significant eruptions. A significant eruption is classified as one that meets at least one of thefollowing criteria: caused fatalities, caused moderate damage (approximately $1 million or more), with a Volcanic Explosivity Index (VEI) of 6 or larger, caused a tsunami,or was associated with a major earthquake.

Source: National Geophysical Data Center / World Data Service (NGDC/WDS)

Note: since this data is very long-term it's expected that most recent data on eruptions will be more complete versus distant historic events.