66. In the winter basketball games, player Xiao Ming scored 23 points, 14 points, 11 points, and 20 points in the sixth, seventh, eighth, and ninth games, respectively. His average score in the first nine games is higher than his average score in the first five games. If his average score in the first ten games is higher than 18 points, then his score in the tenth game must be at least $\qquad$ points.
answer: 29