(1) A person's historical aviation activity level is -

(a) the number of tonne-kilometres of aviation activity performed by the person in 2010;

(b) in the case of a person who fell within Article 3f(1)(a) of the Directive and made a successful special reserve application, the number of tonne-kilometres of aviation activity performed by the person in 2014; or

(c) in the case of a person who fell within Article 3f(1)(b) of the Directive and made a successful special reserve application, the sum of -

(i) the number of tonne-kilometres of aviation activity performed by the person in 2010; and

(ii) the person's aviation activity ratio multiplied by the difference between the number of tonne-kilometres of Annex 1 activities performed by the person in 2014 and the person's threshold figure.

(2) In this article, a person's -