This Google trend chart shows interest in search topics, not just search query. Which means, that trends also include queries that are related to the search topic but do not contain the same exact wording. Explanation from the Google Trends page:
"When you measure interest in a search topic (Tokyo - Capital of Japan) our algorithms count many different search queries that may relate to the same topic (東京, Токио, Tokyyo, Tokkyo, Japan Capital, etc). When you measure interest in a search query (Toyko - Search term), our systems will count only searches including that string of text ("Tokyo")."