为什么中国烟民人口那么多？

[img]http://img.nga.178.com/attachments/mon_201209/14/-47218_5052bca2a2f43.png[/img][img]http://img.nga.178.com/attachments/mon_201209/14/-47218_5052bca2a2f43.png[/img]国人都是怎么沾上烟瘾的？