Plot Real Data and Forecast

I have data Jan. to Sept. How do you start the forecast in July to see an overlap of how accurate the forecast is?

CREATE TABLE [dbo].[Sales](
[Revenue] [float] NULL
) ON [PRIMARY]
GO
INSERT [dbo].[Sales] ([Revenue]) VALUES (847417869000)
INSERT [dbo].[Sales] ([Revenue]) VALUES (311378700000)
INSERT [dbo].[Sales] ([Revenue]) VALUES (75525484000)
INSERT [dbo].[Sales] ([Revenue]) VALUES (16436031000)
INSERT [dbo].[Sales] ([Revenue]) VALUES (177192863000)
INSERT [dbo].[Sales] ([Revenue]) VALUES (562640531000)
INSERT [dbo].[Sales] ([Revenue]) VALUES (73309534000)
INSERT [dbo].[Sales] ([Revenue]) VALUES (329279516000)
INSERT [dbo].[Sales] ([Revenue]) VALUES (650266113000)
GO

library(RODBC, warn.conflicts = FALSE)
conn = odbcConnect("CN")
query <- sqlQuery(conn, "SELECT [Sales]
FROM [dbo].[Sales]")

query
querytimeseries <- ts(query)
plot.ts(querytimeseries)
library(forecast)
querytimeseriesarima <- arima(querytimeseries, order=c(0,0,0))
querytimeseriesarima
library("forecast")
querytimeseriesforecasts <- forecast(querytimeseriesarima, h=5)
querytimeseriesforecasts
plot(querytimeseriesforecasts)