Does anyone know how many people each year in the united states get denied american citizenship? can these?

people appeal this decision, ask for some type of pardon, or wait until retirement until they are able to obtain american citizenship if at all? would the very best and most expensive immigration attorneys in the country be somehow able to obtain citizenship for these people? we're asking because we to know if the government forgives people after a very, very, very long time. does anyone know? can anyone please share some insight? rsvp. thanks.