Fatal Error going to Admin Center

Started getting the following errrror when going to Admin Center. Any suggestions?

Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 32 bytes) in /var/www/…/core/classes/ezdb/ezdb_mysqli.class.php on line 281

Based on the various comments for running our of memory, there does not appear to be one cause. Here is the issue we only have 9000 pireps loaded so far. This is a conversion of an existing airline, when all historical pireps are loaded they will exceed 270,000. Based on this what memory requirements should we expect?