พล็อตปีด้วยค่าเฉลี่ยของการเข้างานเป็นแผนภูมิเส้น และเรียงลำดับแกน x ตามลำดับ asc ไม่จำเป็นต้องใช้ตารางทั้งหมด
Plot year by the average of attendance as a line chart, and sort x axis in asc order.It is not neccessary to use all the tables.
 pitching_postseason:  player_id [ TEXT]  year [ INTEGER]  round [ TEXT]  team_id [ TEXT]  league_id [ TEXT]  w [ INTEGER]  l [ INTEGER]  g [ INTEGER]  gs [ INTEGER]  cg [ INTEGER]  sho [ INTEGER]  sv [ INTEGER]  ipouts [ INTEGER]  h [ INTEGER]  er [ INTEGER]  hr [ INTEGER]  bb [ INTEGER]  so [ INTEGER]  baopp [ TEXT]  era [ NUMERIC]  ibb [ NUMERIC]  wp [ NUMERIC]  hbp [ NUMERIC]  bk [ NUMERIC]  bfp [ NUMERIC]  gf [ INTEGER]  r [ INTEGER]  sh [ NUMERIC]  sf [ NUMERIC]  g_idp [ NUMERIC] 
SELECT year, AVG(attendance) FROM home_game GROUP BY year ORDER BY year