CREATE TABLE bridge (architect_id INT, id INT, name TEXT, location TEXT, length_meters FLOAT, length_feet FLOAT)
CREATE TABLE architect (id TEXT, name TEXT, nationality TEXT, gender TEXT)
CREATE TABLE mill (architect_id INT, id INT, location TEXT, name TEXT, type TEXT, built_year INT, notes TEXT)

How many mills of 'Grondzeiler' type are built in each year? Give me the trend.
SELECT built_year, COUNT(built_year) FROM mill WHERE type = 'Grondzeiler'
SELECT "built_year", COUNT("built_year") FROM "mill" WHERE "type" = 'Grondzeiler'