Table:
Mean Total Time (sec)	RNA2(∼1300 bases)	RNA1(∼3100 bases)
60	150	300	60	150	300
Centered	257.7	232.3	185.7	3228.7	2871.7	2303.9
Optimized	226.6	197.4	164.6	2758.0	2366.0	1907.7
Opti./Cent.	0.88	0.85	0.89	0.85	0.82	0.83

Continue parse the table with markdown style: | Mean Total Time (sec) | <COLSPAN=3> RNA2(∼1300 bases) | <COLSPAN=3> RNA1(∼3100 bases) | 
 | --- | --- | --- | --- | --- | --- | --- | 
 |  | 60 | 150 | 300 | 60 | 150 | 300 | 
 | Centered | 257.7 | 232.3 | 185.7 | 3228.7 | 2871.7 | 2303.9 | 
 | Optimized | 226.6 | 197.4 | 164.6 | 2758.0 | 2366.0 | 1907.7 |


 | Opti./Cent. | 0.88 | 0.85 | 0.89 | 0.85 | 0.82 | 0.83 |