when did viruses appear

Keyword Analysis

Keyword	CPC	PCC	Volume	Score	Length of keyword
when did viruses appear	1.9	0.6	849	47	23
when	1.95	0.3	8667	9	4
did	0.43	0.1	8243	28	3
viruses	1.72	0.8	9020	40	7
appear	0.9	0.2	3903	60	6

Keyword	CPC	PCC	Volume	Score
when did viruses appear	1.84	0.4	9609	83
when did fileless viruses first appear	0.85	0.1	7781	21
when did viruses first appear on earth	1.81	0.4	4678	60
when did computer viruses first appear	0.05	1	823	27
when did viruses first appear	1.78	1	8955	52
when did file-less viruses first appear	0.15	0.5	9731	21
when were viruses first identified	1.59	0.9	5599	95
when did the virus start	1.42	0.7	9704	62
when were viruses discovered	0.76	0.2	6250	25
when was virus first found	0.31	0.9	7333	29
what year did the virus start	1.44	0.8	3922	37
what year were viruses discovered	1.48	0.8	1504	61
the history of viruses	0.03	0.1	5659	93
how long have viruses been around	0.85	0.4	1966	39
history of viruses in the world	0.28	0.6	9005	17
where did the virus originate	0.79	0.6	8984	84
when was the first virus made	1.66	0.6	5203	23
where did the first virus come from	0.72	0.4	5358	75