mysql> select count(*) from invitation where created >= '2008-07-04 00:00:00' and created < '2009-01-01 00:00:00';
+----------+
| count(*) |
+----------+
| 686 |
+----------+
1 row in set (0.09 sec)
mysql> select count(*) from invitation where created >= '2009-01-01 00:00:00' and created < '2010-01-01 00:00:00';
+----------+
| count(*) |
+----------+
| 9529 |
+----------+
1 row in set (0.10 sec)
mysql> select count(*) from invitation where created >= '2010-01-01 00:00:00' and created < '2011-01-01 00:00:00';
+----------+
| count(*) |
+----------+
| 158761 |
+----------+
1 row in set (0.11 sec)