transaction id wraparound

When I run this query

fwdb01=# select current_timestamp,datname,age(datfrozenxid) from
pg_database;

now | datname | age

-------------------------------+-----------+------------

2006-09-28 18:04:24.489935+00 | postgres | 1087834006

2006-09-28 18:04:24.489935+00 | fwdb01 | 2039254861

2006-09-28 18:04:24.489935+00 | template1 | 2039253122

2006-09-28 18:04:24.489935+00 | template0 | 1542808250

(4 rows)

fwdb01=# select current_timestamp,datname,age(datfrozenxid) from
pg_database;

now | datname | age

------------------------------+-----------+------------

2006-09-28 18:10:45.64452+00 | postgres | 1088357075

2006-09-28 18:10:45.64452+00 | fwdb01 | 2039777930

2006-09-28 18:10:45.64452+00 | template1 | 2039776191

2006-09-28 18:10:45.64452+00 | template0 | 1543331319

In approximately 6 minutes, the fwdb01 count has gone up by about 500K.
I am generating about 250K rows for every 6 . I am also running
vacuumdb.

Does vacuumdb generate a lot of transactions that affects this counter.