utf8 and latin1 table size

[Shiv M]

Recently I converted a latin1 character set table to utf8 and to my surprise the size was almost 40% less and average_length was halved on doing so, when in fact I was expecting it to increase in size or at least same as before since latin1 characters map to utf8 single bytes retaining the same length. I am missing something here.

Thanks in advance for any details on what I see below.

Original table...latin1 charset

mysql> show table status like 'XYZ' \G;
*************************** 1. row ***************************
Name: XYZ
Engine: InnoDB
Version: 10
Row_format: Compact
Rows: 2616427
Avg_row_length: 201
Data_length: 436207616
Max_data_length: 0
Index_length: 248381440
Data_free: 7340032
Auto_increment: NULL
Create_time: 2011-07-05 20:24:40
Update_time: NULL
Check_time: NULL
Collation: latin1_swedish_ci
Checksum: NULL
Create_options:
Comment:
1 row in set (0.00 sec)


mysql> ALTER TABLE XYZ CONVERT TO CHARACTER SET utf8;

mysql> show table status like 'XYZ' \G;
*************************** 1. row ***************************
Name: XYZ
Engine: InnoDB
Version: 10
Row_format: Compact
Rows: 2613257
Avg_row_length: 103
Data_length: 270532608
Max_data_length: 0
Index_length: 147849216
Data_free: 5242880
Auto_increment: NULL
Create_time: 2011-07-07 20:24:40
Update_time: NULL
Check_time: NULL
Collation: utf8_general_ci
Checksum: NULL
Create_options:
Comment:
1 row in set (0.00 sec)