The time when unit became active or started is printed after the "@" character.
The time the unit took to start is printed after the "+" character.

graphical.target @30.868s
└─multi-user.target @30.868s
  └─systemd-user-sessions.service @13.686s +77ms
    └─network.target @13.659s
      └─NetworkManager.service @10.865s +2.793s
        └─dbus.service @10.209s +645ms
          └─basic.target @10.207s
            └─sockets.target @10.207s
              └─snapd.socket @10.187s +19ms
                └─sysinit.target @10.157s
                  └─systemd-update-done.service @10.126s +29ms
                    └─ldconfig.service @7.429s +2.670s
                      └─local-fs.target @7.389s
                        └─boot.mount @7.322s +64ms
                          └─[email protected] @6.117s +1.119s
                            └─dev-sdc1.device @584542y 2w 2d 20h 1min 47.331s +8.314s