Since approval for use of tasers in Switzerland by Swiss cantonal police was granted in 2003, usage has been steadily on the increase.

The Swiss Police Technical Commission recorded 18 instances last year, up from 15 cases the previous year, newspaper Neue Zürcher Zeitung reports.

The trend is steadily rising, with thirteen, seven and eight cases recorded in the years 2007 to 2009. Overall, the gun has been used 70 times since its introduction in Switzerland.

Tasers operate by emitting a strong electrical current, disrupting voluntary control of the recipient’s muscles. They have become increasingly popular among police and special forces units in cases concerning mentally disturbed, violent or intoxicated individuals.

Unlike the United States, where tasers can be carried legally in 43 states without a permit, use of tasers in Switzerland is restricted to use only by police and border guards.

In over half of the cases reported in Switzerland last year, the targets were described as being emotionally disturbed. The rest of the numbers were made up of individuals under the influence of either drugs or alcohol.

Amnesty International has voiced concern over the use of taser guns, in particular against the emotionally disturbed, NZZ reports.

The organisation maintains that tasers should only be used when any other weapon would be used.

In half of the cases, the taser was used to still physically violent and aggressive individuals.

Only one person is recorded as being injured in 2011. These injuries were sustained when the recipient fell from the force of the shock.