How much does Studio Ghibli rely on computer animation techniques according to this text?

Studio Ghibli films are mostly hand-drawn using rich water and acrylic paints. The films use traditional methods of making animation where every frame is drawn and colored by hand. Computer animation techniques are used sparingly.[127] All the Studio Ghibli films use bright colors,[128][129] and have a "whimsical and joyful aesthetic".[130]

The films often focus on the lives of youth, especially school children. Common themes include the risks posed by progress to tradition,[131] environmentalism and the natural world,[131][130] independent female protagonists,[128] the cost of war, and youth.[129] 
While the exact percentage isn't known, Studio Ghibli sticks to traditional animation methods as much as possible, only rarely using computer animation.