Mourinho starts pre-season training in his second spell as Chelsea manager at Cobham tomorrow, before flying out with his squad for their tour of Asia on Thursday.
"The first time I went to the States, in 2004 with Chelsea for pre-season, the training session was open-door and there were 10 kids," said Mourinho.
"Nobody cared when we walked in the street. Maybe somebody said, 'Oh, Frank Lampard', but no more than that.
"After two years with the boom of the economic impact of the owner, buying the players, winning the Premier League and reaching the Champions League semi-finals, things changed.
"We went to the States again and had an open training session. This time, there were three or four thousand watching in Los Angeles.