What does the phrase "year-on-year" (see context below) mean? Or, better, can you translate it into Rus/Span.?

Question

"Nokia's year-on-year market share increase was driven primarily by strong gains in China and Asia-Pacific..."

Answer 1

it simply means annual, the increase registered in a business year with respect to the previous one.
In Spanish I would say "el incremento anual de la cuota de mercado". In Russian it would be smth. like "ezhegodnyi vozrast rynkovoi dolyi". Hope that helps

Answer 2

it just really means annually,like year after year