What are the top 5 Dexes?

Could you please elaborate on the top five decentralized exchanges, or Dexes, in the cryptocurrency market? I'm particularly interested in understanding their unique features, popularity, and the reasons behind their ranking. Could you also provide insights into their trading volumes, token offerings, and the overall security measures they implement to safeguard users' assets? Finally, it would be helpful if you could mention any upcoming trends or developments in the Dex space that investors and enthusiasts should keep an eye on.